HUMAN SEROTONIN RECEPTORS, DNA ENCODING THE RECEPTORS, AND USES THEREOF

Abstract: The present invention describes nucleic acid molecules encoding human serotonin receptors, recombinant serotonin receptor proteins, cultured cells expressing recombinant serotonin receptor proteins, antibodies immunoreactive with serotonin receptor proteins, polypeptide serotonin receptor antagonists, oligonucleotide probes used for detecting nucleic acids which encode a human serotonin receptor, and nonhuman transgenic animals which express recombinant human serotonin receptor. Also disclosed are methods for screening for ligand binding to the described serotonin receptors and for serotonin receptor agonists and antagonists, for detection of serotonin receptors in tissues, and for therapeutic treatments involving the described human serotonin receptors.

Description: HUMAN SEROTONIN RECEPTORS, DNA ENCODING THE RECEPTORS, AND USES THEREOF Technical Field The present invention relates generally to the field of serotonin receptors. Specifically, the invention relates to isolated nucleic acid molecules encoding serotonin receptors, to isolated receptor proteins, and to uses of the nucleic acid molecules and proteins in methods for determining ligand binding, detecting expression of serotonin receptors, drug screening and therapeutic treatments involving human serotonin receptors. Background Serotonin (5-hydroxytryptamine, 5-HT) regulates a wide variety of sensory, motor and behavioral functions in the mammalian central nervous system (CNS) . This biogenic amine neurotransmitter is synthesized by neurons in the raphe nuclei of the brain stem that project throughout the CNS, with highest density in basal ganglia and limbic structures. Steinbusch, Handbook of Chemical Neuroanatomv, 3:68-125, Bjorklund et al., eds., Elsevier Science Publishers, B.V., (1984). Serotonergic transmission is thought to be involved with a variety of behaviors and psychiatric disorders including anxiety, sleep regulation, aggression, feeding and depression. Cowen, British J. Psvch.. 159:7-14 (1991); and Lucki, Neurosci. & Biobehav. Rev.. 16:83-93 (1992). Understanding how 5-HT mediates its diverse physiological actions requires the identification and isolation of the pertinent 5-HT receptors . Molecular cloning has indicated that 5-HT receptors belong to at least two protein superfamilies: G-protein-associated receptors which have seven putative transme brane domains (TMDs) (5- HT IA/B/C/D/E ' 5 ~ HT 2 and rat stomach funduε) and ligand- gated ion channel receptors which have four putative TMDs (5-HT j ) . Albert et al., J. Biol. Chem.. 265:5825-5832 (1990); Hamblin et al., Bioche . & Biophvs. Res. Comro.. 184:752-759 (1992); Adham et al., Molee. Pharm.. 41:1-7 (1992); Voigt et al., EMBO J L., 10:4017-4023 (1991); Jin, et al., J. Biol. Chem.. 267:5735-5738 (1992); Maroteaux, et al., Proc. Natl. Acad. Sci. USA. 89:3020-3024 (1992); Julius, et al. , Science. 241:558-564 (1988); Lubbert, et al., Proc. Nat. Acad. Sci. USA. 84:4332-4336 (1987); Hamblin, et al., Mole. Pharm.. 40:143-148 (1991); Zgombick, et al., Mole. Pharm.. 40:1036-1042 (1991); Weinshank, et al., Proc. Natl. Acad. Sci. USA. 89:3630-3634 (1992); Levy, et al., J. Biol. Chem.. 267:7553-7562 (1992); McAllister, et al., Proc. Natl. Acad. Sci. USA. 89:5517-5521 (1992); Pritchett, et al., EMBO J.. 7:4135-4140 (1988); Foguet, et al., EMBO J.. 11:3481- 3487 (1992); and Maricq, et al., Science. 254:432- 437 (1991) . As a serotonin receptor cloning strategy, Libert et al., Science. 244:569-572 (1989), demonstrated that novel G-protein-associated receptors could be identified in a polymerase chain reaction (PCR) using degenerate primers corresponding to strongly conserved sequences within their TMDs. The subtypes of serotonin receptors have been historically distinguished on the basis of their pharmacological binding profiles, on second messenger coupling, and based on physiological roles known for the better characterized serotonin receptors. Most of the characterizing data in the field is not based on the properties of a single purified receptor protein or gene, but rather based on experimental observations using a model tissue. Thus, there is a need for extensive molecular and corresponding pharmacological characterization of serotonin receptors in order to better understand the extent of the subfamilies and the physiological roles each plays. Brief Description of the Invention The invention relates to the discovery, cloning and characterization of several unique serotonin receptors. Thus, in one embodiment, the invention describes a isolated protein that is a serotonin receptor selected from the group consisting of 5-HT 1E . lj(ce , 5- HT 5β , 5-HT 5B and 5-HT 6 . The invention also describes a DNA segment encoding a serotonin receptor selected from the group consisting of 5-HT 1E _ Hke , 5-HT 5α , 5-HT 5B and 5-HT 6 , vectors containing the DNA segments capable of expressing the serotonin receptor, and mammalian cells that contain the vectors and express the serotonin receptors. Also described is a method for determining whether a ligand can bind to a preselected serotonin receptor which comprises; (a) contacting a mammalian cell with a candidate ligand under conditions permitting binding of a known serotonin receptor ligand to the serotonin receptor, wherein the mammalian cell comprises a vector adapted for expressing a serotonin receptor in the mammalian cell, wherein the said comprises a DNA segment encoding the preselected serotonin receptor and expresses cell surface serotonin receptor; and (b) detecting the presence of any of the candidate ligand bound to the cell surface serotonin receptor, and thereby determining whether the ligand binds to the receptor. In a related embodiment, the invention describes a method for screening drugs to identify a candidate drug that can activate a preselected serotonin receptor which comprises; (a) contacting a mammalian cell with the candidate drug under conditions permitting activation of the serotonin receptor by a known serotonin receptor activating drug, the mammalian cell comprising a vector adapted for expressing a serotonin receptor in the mammalian cell, the vector comprising a DNA segment encoding the preselected serotonin receptor, and the mammalian containing a cell surface serotonin receptor; and (b) detecting the activation status of the cell surface serotonin receptor, and thereby determining whether the drug activates the receptor. The invention also describes an isolated nucleic acid molecule probe comprising a nucleic acid segment of at least 10 nucleotides in length having a sequence corresponding to or complementary to a sequence included within the coding region of a nucleotide sequence that encodes a serotonin receptor selected from the group consisting of 5-HT 1E _ Uke , 5-HT 5a , 5-HT 5B and 5-HT 6 . The probe is useful in a variety of diagnostic systems for detecting serotonin receptor genes and mRNA transcripts in vitro and in situ. A therapeutic oligonucleotide of about 10 to 100 nucleotides in length is also described having a sequence capable of hybridizing specifically with a structural protein region of the nucleotide sequence that encodes a serotonin receptor of this invention, as are therapeutic methods for altering serotonin receptor gene expression in a cell comprising administering to a subject an amount of a pharmaceutical composition comprising a physiologically acceptable carrier and the therapeutic oligonucleotide. Still further, the invention describes a serotonin receptor polypeptide having a length of no more than about 100 amino acid residues and a sequence that substantially corresponds to a portion of the sequence of a serotonin receptor of this invention. Also described is an antibody comprising antibody molecules that immunoreact with a serotonin receptor of this invention, including a monoclonal antibody. A transgenic nonhuman mammal is also described expressing a DNA segment that encodes a human serotonin receptor of this invention, and screening methods using the transgenic mammal. Other embodiments will be apparent to one skilled in the art. Brief Description of the Drawings In the figures forming a portion of this disclosure: Figure 1 illustrates the nucleotide sequence and predicted amino acid sequence of the rat MR22 cDNA clone as described in Example 4. The putative transmembrane domains are underlined, a putative N-glycoεylation site is circled and putative protein kinaεe C phosphorylation εiteε are boxed. Figure 2 illustrates the nucleotide sequence and predicted amino acid sequence of the rat REC17 cDNA clone as described in Example 4. The putative transmembrane domains are underlined, two putative N-glycosylation sites are circled and putative protein kinase C phosphorylation sites are boxed. Figure 3 illustrates the nucleotide sequence and predicted amino acid sequence of the rat MR77 genomic clone as described in Example 4. The putative transmembrane domains are underlined. Arrows indicate potential N-linked glycosylation sites. The asterisk is located above the intron splice junction. The sequence upstream of this site in Bold print represents the MR77 cDNA sequence which is different from the genomic clone. The cDNA sequence downstream from the asterisk is identical to the genomic clone (not shown) . Circled and squared amino acids are consensus phosphorylation sites for protein kinase C and calmodulin kinase II, respectively. Amino acids in italics beneath the rat amino acid sequence represent differences with human clone. The nucleotide sequences of the rat and human clones can be accessed from GenBank, accession numbers are L05596 and L05597, respectively. Figures 4A and 4B illustrate the PCR-based detection of MR77 mRNA expression described in Example 4. In Figure 4A, point B corresponds to nucleotide 97 of the MR77 genomic clone shown in Figure 3. The distance between, and including, oligonucleotides 1 and 2 is 563 base pairs on the cDNA clone. The distance between point A and B on the genomic clone is not known. In Figure 4B, the regional distribution of MR77 mRNA expresεion iε shown. cDNAs from the tissues listed were used as templates for the PCR reaction described above (A) . The major band (middle band) migrates at approximately 570 base pairs. The blot was probed with an 32 P-labeled oligonucleotide corresponding to nucleotides 257-278 of the genomic clone. The control lanes 12 and 13 used mRNA templates that had not been reverse transcribed. Figure 5 illustrates the nucleotide and predicted amino acid sequence of the rat REC20 cDNA clone as described in Example 4. The amino acid translation was determined for the longest open reading frame which begins with a methionine. The region surrounding the codon ATG for translation initiation conforms with the consensus sequence described by Kozak, Nuc. Acids Res.. 12:857-872 (1984) . The putative transmembrane spanning regions are underlined and numbered (I-VII) . Potential sites for N-linked glycosylation and protein kinase C phosphorylation are marked beneath the amino acid by solid circles and squares, respectively. Figure 6 illustrates the dendrogram analysis of serotonin G-protein coupled receptor family. This figure demonstrates how subgroups of serotonin (5-HT) receptors including the four novel serotonin receptor proteins of this invention cluster according to sequence similarity. The length of the horizontal line is inversely proportional to primary structure identity between the sequence pairs. Species from which primary structure are derived is as follows: 5-HT 1A B c 2 are rat, 5-HT 1E is human and 5-HT 1D is canine. The Drosophila 5-HTdrol, dro2A, dro2B receptors were included to show sequence relationships. The amino acid sequence data used in generating the dendrogram were compiled and analyzed using the Genetics Computer Group sequence software Lineup and Pileup (Madison, I) . The dendrogram placement of the novel serotonin receptor proteins of this invention, MR22, REC17, MR77 and REC20, is discussed in Example 4E. Figures 7A-7D illustrate the effects of serotonergic agents on the neuronal activity as measured against circadian time in the suprachiasmatic nucleus (SCN) as described in Example 7. The procedures used in measuring the circadian time involving slice preparation and maintenance, electrophysiological recordings, and data analysis were performed as described by Prosser et al., J. Neurosci.. 9:1073-1081 (1989). Slice treatment consisted of stopping perfusion and replacing bath medium for 1 hour with medium containing no additional compounds (=control) or 8-OH-DPAT. In blocking experiments, bath medium was first replaced for 15 minutes with perfusion medium containing either pindolol or ritanserin (dissolved in 100% ethanol and then diluted to the proper concentration) , followed by replacement for 1 hour with medium containing 8-OH-DPAT and either pindolol or ritanserin, followed by an additional 15 minute treatment with medium containing pindolol or ritanserin. This was followed by the normal perfusion medium. Horizontal bars: time of lights-off in donor colony; vertical bars: time of treatment; dotted line: mean time of peak in untreated slices. Detailed Description of the Invention A. Definitions Amino Acid Residue: An amino acid formed upon chemical digestion (hydrolysiε) of a polypeptide at itε peptide linkages. The amino acid residues described herein are preferably in the "L" isomeric form. However, residues in the "D" isomeric form can be substituted for any L-amino acid residue, as long as the desired functional property is retained by the polypeptide. NH 2 refers to the free amino group present at the amino terminus of a polypeptide. COOH refers to the free carboxy group present at the carboxy terminus of a polypeptide. In keeping with standard polypeptide nomenclature (described in J. Biol. Chem.. 243:3552-59 (1969) and adopted at 37 CFR §1.822(b) (2) ) , abbreviations for amino acid residues are shown in the following Table of Correspondence: TABLE OF CORRESPONDENCE SYMBOL AMINO ACID 1-Letter 3-Letter Y Tyr tyrosine G Gly glycine F Phe phenylalanine M Met methionine A Ala alanine S Ser serine I He isoleucine L Leu leucine T Thr threonine V Val valine P Pro proline K Lys lysine H His histidine Q Gin glutamine E Glu glutamic acid Z Glx Glu and/or Gin W Trp tryptophan R Arg arginine D Asp aspartic acid N Asn asparagine B Asx Asn and/or Asp C Cys cysteine X Xaa Unknown or other It should be noted that all amino acid residue sequences represented herein by formulae have a left- to-right orientation in the conventional direction of amino terminus to carboxy terminus. In addition, the phrase "amino acid residue" is broadly defined to include the amino acids listed in the Table of Correspondence and modified and unusual amino acids, such as those listed in 37 CFR 1.822(b)(4), and incorporated herein by reference. Furthermore, it should be noted that a dash at the beginning or end of an amino acid residue sequence indicates a peptide bond to a further sequence of one or more amino acid residues or a covalent bond to an amino-terminal group such as NH 2 or acetyl or to a carboxy-terminal group such as COOH. Recombinant DNA frDNA) molecule: a DNA molecule produced by operatively linking two DNA segments. Thus, a recombinant DNA molecule is a hybrid DNA molecule comprising at least two nucleotide sequences not normally found together in nature. rDNA'ε not having a common biological origin, i.e., evolutionarily different, are said to be "heterologous". Vector: a rDNA molecule capable of autonomous replication in a cell and to which a DNA segment, e.g., gene or polynucleotide, can be operatively linked so as to bring about replication of the attached segment. Vectors capable of directing the expresεion of geneε encoding for one or more polypeptides are referred to herein as "expression vectors". Receptor: A receptor is a molecule, such as a protein, glycoprotein and the like, that can specifically (non-randomly) bind to another molecule. Antibody; The term antibody in its various grammatical forms is used herein to refer to immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, i.e., molecules that contain an antibody combining site or paratope. Exemplary antibody molecules are intact immunoglobulin molecules, substantially intact immunoglobulin molecules and portions of an immunoglobulin molecule, including those portions known in the art as Fab, Fab', F(ab') 2 and F(v). Antibody Combining Site: An antibody combining site is that structural portion of an antibody molecule comprised of a heavy and light chain variable and hypervariable regions that specifically binds (immunoreacts with) an antigen. The term immunoreact in its various forms means specific binding between an antigenic determinant-containing molecule and a molecule containing an antibody combining site such as a whole antibody molecule or a portion thereof. Monoclonal Antibody: A monoclonal antibody in its various grammatical forms refers to a population of antibody molecules that contain only one species of antibody combining site capable of immunoreacting with a particular epitope. A monoclonal antibody thus typically displays a single binding affinity for any epitope with which it immunoreacts. A monoclonal antibody may therefore contain an antibody molecule having a plurality of antibody combining sites, each immunospecific for a different epitope, e.g., a bispecific monoclonal antibody. Although historically a monoclonal antibody was produced by immortalization of a clonally pure immunoglobulin secreting cell line, a monoclonally pure population of antibody molecules can also be prepared by the methods of the present invention. Upstream: In the direction opposite to the direction of DNA transcription, and therefore going from 5' to 3" on the non-coding strand, or 3' to 5' on the mRNA. Downstream: Further along a DNA sequence in the direction of sequence transcription or read out, that is traveling in a 3'- to 5'-direction along the non- coding strand of the DNA or 5 1 - to 3'-direction along the RNA transcript. Reading Frame: Particular sequence of contiguous nucleotide triplets (codons) employed in translation that define the structural protein encoding-portion of a gene, or structural gene. The reading frame depends on the location of the translation initiation codon. B. Serotonin Receptor Proteins The serotonin receptors are known in the art as a family of mammalian proteins that function as receptorε for a variety of bioactive molecules which generally fall into the category of serotonin analogs. Based on the background review of the art, it is seen that there are many different serotonin receptors, which differ in amino acid residue sequence, tissue location, and function based on their ligand specificity. The present invention provides the description of four new serotonin receptors, represented herein by the four prototype receptors MR77, MR22, REC17 and REC20, and that fall into three new serotonin subfamily classifications, 5 ~HT 1E . like , 5-HT 5 , and 5-HT 6 . The MR77 serotonin receptor is the prototype receptor for the 5-HT 1E . like subfamily. The MR22 and REC17 serotonin receptors are prototype receptors for the 5- HT 5 subfamily, and can be further subdivided in to two subfamily types, 5-HT 5β and 5-HT 5β , for REC17 and MR22, respectively. The REC20 serotonin receptor is the prototype receptor for the 5-HT 6 subfamily. The characterization of a serotonin receptor as a member of a serotonin receptor subfamily is based herein on the amino acid residue sequence homology of the receptor protein compared to other serotonin receptor amino acid sequences. Thus, a protein is considered to be a serotonin receptor of this invention if the protein has a total amino acid residue sequence homology of at least 60% with a prototype sequence, and is furthermore considered to be a member of that prototype's subfamily. Variations are known in isolates of serotonin receptors, and such variations are not to be construed as limiting. For example, allelic variation within a mammalian species can tolerate a several percent difference between isolates of a type of serotonin receptor, which differences comprise non-deleterious variant amino acid residues. Thus a protein of about 95% homology, and preferably at least 98% homology, to a disclosed serotonin receptor is considered to be an allelic variant of the disclosed serotonin receptor, and therefore is considered to be a serotonin receptor of this invention. In addition, "type" variantε of a serotonin receptor are members of a subfamily exhibiting about 60% to 95% homology to each other, and more typically exhibiting about 60-80% homology. As an example, the REC17 and MR22 serotonin receptor proteins of this invention are shown herein to have approximately 68% sequence homology to one another, thereby belonging to the same subfamily, and yet are designated as different serotonin receptor types. A serotonin receptor is considered to be of the same "type" as a disclosed serotonin receptor if it has at least about 60% homology, and preferably 60-95% homology, to a disclosed serotonin receptor. A serotonin receptor of this invention can be in a variety of forms, depending upon the use therefor, as described herein. For example, a serotonin receptor can be isolated from a natural tissue and be present in a composition in an isolated form, ie. , comprising at least about 0.1 percent by weight of the total composition, preferably at least 1%, and more preferably at least about 90%. Particularly preferred is a substantially pure preparation of receptor, that is at least 90% by weight, and more preferably at least 99% by weight. Alternatively, a serotonin receptor of this invention can be recombinant protein, that is, produced by recombinant DNA (rDNA) methods as described herein. A recombinant serotonin receptor need not necessarily be substantially pure, or even isolated, to be useful in certain embodiments, although recombinant production methods are a preferred means to produce a source for further purification to yield an isolated or substantially pure receptor composition. A recombinant serotonin receptor can be present in or on a mammalian cell line or in crude extracts of a mammalian cell line. In one embodiment, a serotonin receptor is substantially free of serotonin receptors from other serotonin subfamilies, so that the purity of a receptor reagent and freedom from pharmacologically distinct receptors affords use in the screening methods. The recombinant production methods are ideally suited to produce absolute purity in this regard, although biochemical purification methods from natural sources are also contemplated. In this regard, a serotonin receptor is substantially free from other serotonin receptors if there are insufficient other receptors such that pharmacological cross-reactivity is not detected in conventional screening assays for ligand binding. An isolated or recombinant serotonin receptor of this invention can be used for a variety of purposes, as described further herein. The receptor can be used as an immunogen to produce antibodies immunoreactive with a serotonin receptor. The receptor can be used in in vitro ligand binding assays for identifying ligand binding specificities, and to characterize candidate pharmaceutical compounds useful for modulating serotonin receptor function. Other uses will be readily apparent to one skilled in the art. Furthermore, the invention contemplates analogs of a serotonin receptor of this invention. An analog is a man-made variant which exhibits the qualities of a serotonin receptor of this invention in terms of immunological reactivity, ligand binding capacity and the like functional properties of a serotonin receptor of this invention. An analog can therefore be a cleavage product of a serotonin receptor, can be a polypeptide corresponding to a portion of a serotonin receptor, and can be serotonin receptor polypeptide in which a membrane anchor has been removed, to name a few permutations. Insofar as the present disclosure identifies serotonin receptors from different mammalian species, the present invention is not to be limited to a serotonin receptor derived from one or a few mammalian species. Thus, the invention contemplates a mammalian serotonin receptor of this invention, which receptor can be derived, by rDNA or biochemical purification from natural sources, from any of a variety of species including man, mouse, rabbit, rat, dog, cat, sheep, cow, and the like mammalian species, without limitation. Human and agriculturally relevant animal species are particularly preferred. 1. Serotonin Receptor Subfamily 5-HT Ukc In one embodiment, a 5-HT 1E . ljke serotonin receptor in its various embodiments is contemplated. The prototype receptors of this subfamily are MR77 derived from rat hypothalamus or a human genomic library, as described herein. The amino acid residue sequence of human MR77 is shown in SEQ ID NO 9. The amino acid residue sequence of rat MR77 is shown in SEQ ID NO 7. 2. Serotonin Receptor Subfamily 5-HT 5 In another embodiment, a 5-HT 5 serotonin receptor in its various embodiments is contemplated. The prototype receptors of this subfamily are REC17 and MR22 derived from rat hypothalamus, as described herein, which represent two receptor types in this subfamily. The amino acid residue sequence of rat REC17 is shown in SEQ ID NO 4. The amino acid residue sequence of rat MR22 is shown in SEQ ID NO 2. 3. Serotonin Receptor Subfamily 5-HT In another embodiment, a 5-HT 6 serotonin receptor in its various embodiments is contemplated. The prototype receptor of this subfamily is REC20 derived from rat hypothalamus, as described herein. The amino acid residue sequence of rat REC20 is shown in SEQ ID NO 11. A serotonin receptor of this invention can be prepared by a variety of means, although expression in a mammalian cell using a rDNA expression vector is preferred. Exemplary production methods for a recombinant serotonin receptor are described in the Examples, and include the production of MR77, REC17, MR22 and REC20. Thus, the invention also provides a method for the production of isolated serotonin receptor comprising inducing cells to express a serotonin receptor of this invention, recovering the receptor from the resulting cells, and purifying the receptor so recovered by biochemical fractionation methods, using a specific antibody of this invention, or other chemical procedures. The inducing step can comprise inserting a rDNA vector encoding a serotonin receptor of this invention, which rDNA is capable of expressing the receptor, into a suitable host cell, and expressing the vector's serotonin receptor gene. C. Nucleic Acid Molecules The amino acid residue sequence of a protein or polypeptide is directly related via the genetic code to the deoxyribonucleic acid (DNA) sequence of the structural gene that codes for the protein. Thus, a structural gene or DNA segment can be defined in terms of the amino acid residue sequence, i.e., protein or polypeptide, for which it codes. An important and well known feature of the genetic code is its redundancy. That iε, for most of the amino acids used to make proteins, more than one coding nucleotide triplet (codon) can code for or designate a particular amino acid residue. Therefore, a number of different nucleotide sequences may code for a particular amino acid residue sequence. Such nucleotide sequences are considered functionally equivalent since they can result in the production of the same amino acid residue sequence in all organisms. Occasionally, a methylated variant of a purine or pyrimidine may be incorporated into a given nucleotide sequence. However, such methylations do not affect the coding relationship in any way. A nucleic acid molecule is any polynucleotide, whether it be a polyribonucleotide of polydeoxyribonucleotide, ie. , RNA or DNA, or analogs thereof. In preferred embodiments, a nucleic acid molecule is in the form of a segment of duplex DNA, although for certain molecular biological methodologies, single-stranded DNA or RNA is preferred. The DNA segments of the present invention are characterized aε including a DNA εequence that encodes a serotonin receptor of this invention. That iε, the DNA segments of the present invention are characterized by the presence of a serotonin receptor εtructural gene. Preferably the gene is present as an uninterrupted linear serieε of codonε where each codon codeε for an amino acid reεidue found in the εerotonin receptor protein, i.e., a gene free of intronε. One preferred embodiment iε a DNA εegment that codes an amino acid residue sequence that defines a serotonin receptor protein corresponding in sequence one of the serotonin receptors MR77, REC17, MR22 or REC20, and the DNA segment is capable of expressing the serotonin receptor. A preferred DNA segment codeε for an amino acid residue sequence substantially the same as, and preferably consisting essentially of, the sequence shown in the sequence listing SEQ ID NOs 2, 4, 7, 9 or 11. Particularly preferred DNA segments have a εequence shown in SEQ ID NOs 1, 3, 5, 8 or 10. Representative and preferred DNA segments are described in the Examples. Homologous DNA and RNA sequences that encode the above serotonin receptors are also contemplated. DNA segments (i.e., synthetic oligonucleotides) that encode serotonin receptor proteins can easily be synthesized by chemical techniques, for example, the phosphotriester method of Matteucci, et al., (J. Am. Chem. Soc.. 103:3185-3191, 1981) or using automated synthesis methods. In addition, larger DNA segments can readily be prepared by well known methods, such as synthesis of a group of oligonucleotides that define the DNA segment, followed by hybridization and ligation of oligonucleotides to build the complete segment. Of course, by chemically synthesizing the coding sequence, any desired modifications can be made simply by substituting the appropriate bases for those encoding the native amino acid residue sequence. Furthermore, DNA segments consisting essentially of structural genes encoding a serotonin protein can be obtained from recombinant DNA molecules containing a gene that defines a serotonin receptor of this invention, and can be subsequently modified, as by site directed mutagenesiε, to introduce any desired substitutions. 1. Cloning Serotonin Receptors Serotonin receptors of this invention can be cloned by a variety of cloning methods and from any mammalian species. The cloning is based on the observation that there is a significant degree of homology between mammalian species for any given serotonin receptor of this invention, and therefor can be carried according to the general methods described in the Examples, using nucleic acid homology strategies. A typical degree of homology required to successfully clone a serotonin receptor of the same subfamily from a different species as is disclosed herein is at least about 80% homologous at the DNA level, and at least about 90% homologous at the protein level. Preferred cloning strategies for isolating a nucleic acid molecule that encodes a serotonin receptor molecule of this invention are described in the Examples, and includes the recitation of polynucleotide probes useful for the screening of librarieε of nucleic acid molecules believed to contain a target serotonin receptor gene. Sources of libraries for cloning a serotonin receptor gene of this invention can include genomic DNA or messenger RNA (mRNA) in the form of a cDNA library from a tissue believed to expresε a serotonin receptor of this invention. Preferred tissueε are brain tiεεues, particularly hypothalamus. 2. Oligonucleotides The invention also contemplateε oligonucleotides useful for methods to detect the presence of a serotonin receptor gene or gene transcript (mRNA) in a tissue by diagnostic detection methods based on the specificity of nucleic acid hybridization or primer extension reactions. Thus, in one embodiment, any polynucleotide probe having a sequence of a portion of a serotonin receptor gene of this invention, or a related and specific sequence, is contemplated. Particularly preferred are polynucleotides containing a portion of the nucleotide sequence shown in SEQ ID NOs 1, 3, 5, 8 or 10 that encode MR77, REC17, MR22 or REC20. Hybridization probes can be of a variety of lengths from about 10 to 5000 nucleotides long, although they will typically be about 20 to 500 nucleotides in length. Hybridization methods are extremely well known in the art and will not be described further here. In a related embodiment, detection of serotonin receptor genes can be conducted by primer extension reactions such as the polymerase chain reaction (PCR) . To that end, PCR primers are utilized in pairs, as is well known, based on the nucleotide sequence of the gene to be detected. Particularly preferred PCR primers can be derived from any portion of a serotonin receptor DNA εequence, but are preferentially from regions which are not conserved in cell receptors, particularly cell membrane receptors, such as the protein region that is an intracellular on extracellular loop area of the sequence. A preferred PCR primer pair useful for detecting MR77 have the nucleotide sequences: CAAGCAAGTAGGATTGCAAAG, and CACAAGCTTTTGGAATGCTTT, and correspond to nucleotides 870-890 and the reverse complement of 1310-1290, respectively (SEQ ID NOs 72 and 73) . Nucleotide primers from the corresponding region of the other serotonin receptors described herein are readily prepared and used to as PCR primers for detection of the presence or expression of the corresponding receptor gene. 3. Expreεsion Vectors In addition, the invention contemplates a recombinant DNA molecule (rDNA) containing a DNA segment of this invention encoding a serotonin receptor described herein. A rDNA can be produced by operatively linking a vector to a DNA segment of the present invention. As used herein, the term "vector" refers to a DNA molecule capable of autonomous replication in a cell and to which another DNA segment can be operatively linked so as to bring about replication of the attached segment. A vector adapted for expression of a gene product and capable of directing the expression of a serotonin receptor gene is referred to herein as an "expression vector". Thus, a recombinant DNA molecule is a hybrid DNA molecule comprising at least two nucleotide sequences not normally found together in nature. The choice of vector to which a DNA segment of the present invention is operatively linked depends directly, as is well known in the art, on the functional properties desired, e.g., protein expression, and the host cell to be transformed, these being limitations inherent in the art of conεtructing recombinant DNA molecules. However, a vector contemplated by the present invention is at least capable of directing the replication, and preferably also expression, of a serotonin receptor structural gene included in DNA segments to which it is operatively linked. In preferred embodiments, a vector contemplated by the present invention includes a procaryotic replicon, i.e., a DNA sequence having the ability to direct autonomous replication and maintenance of the recombinant DNA molecule extrachromosomally in a procaryotic host cell, such as a bacterial host cell, transformed therewith. Such replicons are well known in the art. In addition, those embodiments that include a procaryotic replicon also include a gene whose expression confers drug resistance to a bacterial host transformed therewith. Typical bacterial drug resistance genes are those that confer resistance to ampicillin or tetracycline. Those vectors that include a procaryotic replicon can also include a procaryotic promoter capable of directing the expression (transcription and translation) of a serotonin receptor gene in a bacterial host cell, such as E. coli. transformed therewith. A promoter is an expression control element formed by a DNA sequence that permits binding of RNA polymerase and transcription to occur. Promoter sequences compatible with bacterial hosts are typically provided in plasmid vectors containing convenient restriction sites for insertion of a DNA segment of the present invention. Typical of such vector plasmids are pUC8, pUC9, pBR322 and pBR329 available from Biorad Laboratories, (Richmond, CA) and pPL and pKK223 available from Pharmacia, Piscataway, N.J. Expresεion vectorε compatible with eucaryotic cells, preferably those compatible with vertebrate cells, can also be used to form the recombinant DNA molecules of the present invention. Eucaryotic cell expression vectors are well known in the art and are available from several commercial sources. Typically, such vectors are provided containing convenient restriction sites for insertion of the desired DNA segment. Typical of such vectors are pSVL and pKSV-10 (Pharmacia) , pBPV-l/pML2d (International Biotechnologies, Inc.), pTDTl (ATCC, #31255), pRc/CMV (Invitrogen, Inc.), the vector pCMV4 described herein, and the like eucaryotic expression vectors. In preferred embodiments, the eucaryotic cell expression vectors used to construct the recombinant DNA molecules of the present invention include a selection marker that is effective in an eucaryotic cell, preferably a drug resiεtance selection marker. A preferred drug resistance marker is the gene whose expression results in neomycin resistance, i.e., the neomycin phosphotransferase (neo) gene. Southern et al., J. Mol. Appl. Genet.. 1:327-341 (1982). Alternatively, the selectable marker can be present on a separate plasmid, and the two vectors are introduced by co-transfection of the hoεt cell, and εelected by culturing in the appropriate drug for the selectable marker. 4. Inhibitory Nucleic Acids In accordance with one embodiment of the invention, nucleic acid molecules can be used in methodologies for the inhibition of serotonin receptor gene expression, thereby inhibiting the function of the receptor by blocking its expreεεion. To that end, the invention contemplates iεolated nucleic acid molecules, preferably single-stranded nucleic acid molecules (oligonucleotides) , having a sequence complementary to a portion of a structural gene encoding a serotonin receptor of this invention. Typical oligonucleotides for this purpose are about 10 to 5,000, preferably about 20-1000, nucleotides in length and have a sequence capable of hybridizing specifically with a structural protein region of the nucleotide sequence that encodes a serotonin receptor of this invention. In one embodiment, the invention contemplates repetitive units of the nucleotide sequence complementary to a portion of a serotonin receptor structural gene so as to present multiple sites for complementary binding to the structural gene. This feature may be provided in a single nucleic acid segment having repeating sequences defining multiple portions of a structural gene, by physical conjugation of DNA segments each containing a single portion of a structural gene, or a combination thereof comprising conjugates of DNA segments, each having one or more sequences complementary to a structural gene. It is also contemplated that nucleotide base modifications can be made to provide certain advantages to a DNA segments of this invention, referred to as nucleotide analogs. A nucleotide analog refers to moieties which function similarly to nucleotide sequences in a nucleic acid molecule of this invention but which have non-naturally occurring portions. Thus, nucleotide analogs can have altered sugar moieties or inter-sugar linkages. Exemplary are the phosphorothioate and other sulfur-containing species, analogs having altered base units, or other modifications consistent with the spirit of this invention. Preferred modifications include, but are not limited to, the ethyl or methyl phosphonate modifications disclosed in U.S. Patent No. 4,469,863 and the phosphorothioate modified deoxyribonucleotides described by LaPlanche et al., Nucl. Acids Res.. 14:9081, 1986; and Stec et al., J. Am. Chem. Soc.. 106:6077, 1984. These modifications provide resistance to nucleolytic degradation, thereby contributing to the increased half-life in therapeutic modalities. Preferred modificationε are the modifications of the 3'-terminus using phosphothioate (PS) sulfurization modification described by Stein et al., Nucl. Acids Res.. 16:3209, 1988. In accordance with the methods of this invention in certain preferred embodiments, at least some of the phosphodiester bonds of the nucleotide sequence can be substituted with a structure which functions to enhance the ability of the compositions to penetrate into the region of cells where the serotonin receptor structural gene to be inhibited iε located. It iε preferred that such linkages be sulfur containing as discussed above, such as phosphorotioate bonds. Other substitutions can include alkyl phosphothioate bonds, N-alkyl phosphoramidates, phoεphorodithioateε, alkyl phosphonates, and short chain alkyl or cycloalkyl structures. In accordance with other preferred embodiments, the phosphodiester bonds are substituted with structureε which are, at once, εubstantially non- ionic and non-chiral. D. Cell Lines Expressing Serotonin Receptors The invention also conte plateε a host cell transformed with a recombinant DNA (rDNA) molecule of the present invention. The host cell can be either procaryotic or eucaryotic, although eucaryotic cells are preferred, particularly mammalian cells. Preferred cells are isolated, that iε, substantially homogeneous and therefor free from other cell types or other cells having different serotonin receptor subfamily members or types. A cell expressing a serotonin receptor of this invention has a variety of uses according to this invention. Particularly preferred are uses in panels of cell lines, each expressing a different serotonin receptor subfamily (or type) member for the purpose of screening pharmaceutical compound banks for the presence of receptor-specific ligands, i.e., in drug screening assays as described herein. Thus, particularly preferred are cells containing a rDNA molecule that expresses a serotonin receptor protein of this invention, and particularly that express a serotonin receptor as a cell surface receptor protein. Eucaryotic cells useful for expression of a serotonin receptor protein are not limited, so long as the cell line is compatible with cell culture methods and compatible with the propagation of the expression vector and expression of the serotonin receptor protein gene product. Preferred eucaryotic host cells include yeast and mammalian cells, preferably vertebrate cells such as those from a mouse, rat, monkey or human fibroblastic cell line. Preferred eucaryotic host cellε include Chineεe hamster ovary (CHO) cells available from the ATCC as CCL61, NIH Swiss mouse embryo cells NIH/3T3 (ATCC CRL 1658) , baby hamster kidney cells (BHK), COS-7, COS-1, HEK293 (ATCC CRL 1573), Ltk-1, AV-12 (ATCC CRL 9595), and the like eucaryotic tissue culture cell lines. Particularly preferred and exemplary are HELA cells (ATCC CCL 2) or the COS-M6 cell, a subclone of COS-7 obtainable from J.L. Goldstein (Univ. of Texas Health Sciences, Dallas) described herein. Transformation of appropriate cell hosts with a recombinant DNA molecule of the present invention is accomplished by well known methods that typically depend on the type of vector used. With regard to transformation of procaryotic host cells, see, for example, Cohen et al., Proc. Natl. Acad. Sci. USA. 69:2110 (1972) ; and Maniatis et al., Molecular Cloning, A Laboratory Mammal. Cold Spring Harbor Laboratory, Cold Spring Harbor, NY (1982) . With regard to transformation of vertebrate cells with vectors containing rDNAs, see, for example, Graham et al., Virol.. 52:456 (1973); Wigler et al., Proc. Natl. Acad. Sci. USA. 76:1373-76 (1979) , and the teachings herein. Successfully transformed cells, i.e., cellε that contain a rDNA molecule of the present invention, can be identified by well known techniques. For example, cells resulting from the introduction of an rDNA of the present invention can be cloned to clonally homogeneous cell populations that contain the rDNA. Cells from those colonies can be harvested, lysed and their DNA content examined for the presence of the rDNA using a method such as that deεcribed by Southern, J. Mol. Biol.. 98:503 (1975) or Berent, et al., Biotech.. 3:208 (1985) . In addition to directly assaying for the presence of rDNA, succesεful transformation can be confirmed by well known immunological methods when the rDNA is capable of directing the expreεεion of εerotonin receptor, or by the detection of the εerotonin binding activity of the serotonin receptor. For example, cells successfully transformed with an expression vector produce proteins displaying serotonin receptor antigenicity or biological activity. Samples of cells suspected of being transformed are harvested and assayed for either serotonin biological activity or antigenicity. Thus, in addition to the transformed host cells themselves, the present invention also contemplates a culture of those cells, preferably a monoclonal (clonally homogeneous) culture, or a culture derived from a monoclonal culture, in a nutrient medium. Preferably, the culture also contains a protein displaying serotonin receptor antigenicity or biologically activity. Nutrient media useful for culturing transformed host cells are well known in the art and can be obtained from several commercial sources. In embodiments wherein the host cell is mammalian, a "serum-free" medium can be used. E. Methods for Identifying a Serotonin Receptor Ligand As discussed in the background, studies on the individual subfamily and subtype serotonin receptors that have been previously described in the published literature reveal characteristic differences in their abilities to bind a number of ligands. However, the structural basis of the distinct ligand- binding properties is not known. Physiologists and pharmacologists classify these different serotonin receptors to different anatomical locations, to different physiological functions and thus to performing different roles in the body to the extent the known receptors are understood. The ability to selectively bind/modulate function of a serotonin receptor by a ligand is at the heart of useful serotonin receptor pharmacology, and depends on identifying pharmacological molecules which can act a selective ligands for one species of serotonin receptor and not the others. To that end, the elucidation of new serotonin receptors, such as those described herein, provides valuable tools for the search for selective ligands, tools that are useful in ligand binding assays, and in screening assayε which indicate selective drug responεe depending on the serotonin receptor. Thus, the invention contemplateε methodε for determining whether a ligand binds to, and preferably whether the ligand activates, a preselected serotonin receptor. The method comprises (1) contacting a cell comprising a recombinant DNA molecule that encodes and expresses a serotonin receptor of this invention under conditions permitting binding of ligands known to bind the serotonin receptor with a candidate ligand, and (2) detecting the presence of the candidate ligand bound to the serotonin receptor, thereby determining whether the ligand binds to the serotonin receptor. The receptor is typically a cell surface protein when expressed by the above cells. It is also possible to use the above method to determine whether the ligand which binds to the εerotonin receptor also activates or motivateε the receptor'ε function. Thus, by evaluating in the detecting step whether the εerotonin receptor iε activated, one determineε whether the ligand iε bioactive. Methods for detecting activation of the εerotonin receptor can vary, but typically involve measuring changes in intracellular levels of a secondary messenger effected as a result of ligand binding. Exemplary measurements are described in the Examples. Thus, a related embodiment contemplateε a method for screening drugs to identify a candidate that can activate a preselected serotonin receptor. The method comprises (a) contacting a mammalian cell with said candidate drug under conditions permitting activation of said serotonin receptor by a known serotonin receptor activating drug, said mammalian cell comprising a vector adapted for expressing a serotonin receptor in said mammalian cell, said vector comprising a DNA segment encoding said preselected serotonin receptor selected from the group consisting of 5-HT 1E . ke , 5-HT 5β , 5-HT 5β and 5-HT 6 and said mammalian containing a cell surface serotonin receptor expressed from said vector; and (b) detecting the activation status of said cell surface serotonin receptor, and thereby determining whether the drug activates said receptor. In a related embodiment, the screening methods can utilize a panel of cell lines each with a different serotonin receptor, thereby providing a panel of serotonin receptors for screening a ligand. The panel can comprise the serotonin receptors of this invention, and can optionally include other serotonin receptors, thereby rendering the panel even more complete. The production of binding data for a ligand against several different serotonin receptors is referred to as a binding profile. The data in the Examples illustrates a binding profile for a large variety of known serotonin receptor ligands. The profile illustrates that each ligand typically exhibits a different pattern across a series of different serotonin receptors. Similarly, the profile illustrateε that each serotonin receptor of this invention is unique in its ligand binding profile, when compared to the profile for a known serotonin receptor. In a related embodiment, the invention contemplates methodε for evaluating the therapeutic effectiveneεs of a candidate serotonin receptor ligand in vivo. The in vivo evaluation method involves the use of a transgenic animal as described herein. The transgenic animal can be a "knockout" animal, i.e., having the gene for a target serotonin receptor removed or otherwise defective. In this embodiment, the invention comprises screening for ligands which replenish deficiencies in the serotonin receptor gene that has been knocked out (mutated) . The method comprises administering a test amount of a serotonin receptor ligand to be evaluated to the knockout animal, and observing changes in the symptoms indicative of the genetic deficiency, and thereby observing the effectiveness of the ligand at modifying those symptoms. In a related embodiment, the invention contemplates a drug screening method using a knockout animal which haε a human serotonin receptor transgene, that iε, the animal is reconstituted with a human serotonin receptor gene. The method involves administering a test amount of a serotonin receptor ligand to be evaluated to the reconstituted knockout animal, and observing changes in the symptomε in the animal aεεociated with the adminiεtered ligand, and thereby observing the effectiveness of the ligand at modifying those symptoms mediated by the human serotonin receptor gene. A further related embodiment involves a screening method in which the reconstituted gene is a mutant serotonin receptor gene, which mutation reflects a known human genetic deficiency. Thus the reconstituted animal provides a model system for studying the defective human gene, and its effect on a whole organism. Furthermore, the reconstituted animal is ideal for screening drugs for effectiveness in treating the symptoms associated with the serotonin receptor gene deficiency. The preparation of a knockout animal, and reconstituting the serotonin receptor gene in the knockout that was removed, is described elsewhere herein. F. Polypeptides As used herein, the phrase "serotonin receptor polypeptide" refers to a polypeptide having an amino acid residue sequence that comprises an amino acid residue sequence that corresponds, and preferably is identical, to a portion of a serotonin receptor of this invention. A serotonin receptor polypeptide of the present invention has a variety of uses according to the present invention. Thuε, a serotonin receptor polypeptide of this invention is characterized by its ability to immuno- logically mimic an epitope (antigenic determinant) expressed by a serotonin receptor of this invention. Such a polypeptide is useful herein as a component in an inoculum for producing antibodies that immunoreact with native serotonin receptor. Representative and preferred serotonin receptor polypeptides for use as an immunogen in an inoculum are shown in Tables 3 and 4 herein. As used herein, the phrase "immunologically mimic" in its various grammatical formε refers to the ability of a serotonin receptor polypeptide of this invention to immunoreact with an antibody of the present invention that recognizes a conserved native epitope of a serotonin receptor as defined herein. It should be understood that a subject polypeptide need not be identical to the amino acid residue sequence of a serotonin receptor, so long as it includes the required sequence. In addition, certain serotonin receptor polypeptides derived from ligand binding portions of the serotonin receptor have capacity to inhibit the binding of a ligand that would normally bind the serotonin receptor. Such inhibitors of ligand binding are referred to as therapeutic polypeptides because of their inhibitory capacity. A serotonin receptor polypeptide is preferably no more than about 200 amino acid reεidueε in length for reaεonε of ease of synthesis. Thus, it more preferred that a serotonin receptor polypeptide be no more that about 100 amino acid residues, still more preferably no more than about 50 residues, and most preferably lesε than 30 amino acid reεidueε in length. In one embodiment, a MR77 serotonin receptor polypeptide of the present invention has a length of no more than about 100 amino acid residues, has an amino acid residue sequence that corresponds to the sequence of human MR77 shown in SEQ ID NO 9, respectively, and includes an amino acid residue sequence represented by a formula selected from the group consisting of: -MIKEELNGQVLLESGEK-, and (SEQ ID NO 36) -HSTVKSPRSELKGEKSWR-. (SEQ ID NO 37) An exemplary and preferred polypeptide in this embodiment has an amino acid residue sequence selected from the group consisting of: MIKEELNGQVLLESGEK, and (SEQ ID NO 36) HSTVKSPRSELKGEKSWR. (SEQ ID NO 37) In a related embodiment, a MR22 serotonin receptor polypeptide of the present invention has a length of no more than about 100 amino acid residueε, has an amino acid residue sequence that corresponds to the sequence of MR22 shown in SEQ ID NO 2, and includes an amino acid residue sequence represented by a formula selected from the group consisting of: -WTITRHLQYTLRTRRR- , (SEQ ID NO 38) -WPLPATTQAKEAPQESETV-, (SEQ ID NO 39) -RATVAFQTSGDSWREQKEKR-, and (SEQ ID NO 40) -KNYNNAFKSLFTKQR- , (SEQ ID NO 41) An exemplary and preferred polypeptide in this embodiment has an amino acid residue sequence selected from the group consisting of: WTITRHLQYTLRTRRR, (SEQ ID NO 38) WPLPATTQAKEAPQESETV, (SEQ ID NO 39) RATVAFQTSGDSWREQKEKR, and (SEQ ID NO 40) KNYNNAFKSLFTKQR, (SEQ ID NO 41) In a related embodiment, a REC17 serotonin receptor polypeptide of the present invention has a length of no more than about 100 aminc acid reεidues, has an amino acid reεidue εequence that corresponds to the sequence of REC17 εhown in SEQ ID NO 4, and includes an amino acid residue sequence represented by a formula selected from the group consisting of: -VSPIPEAVEVKDASQHPQM-, and (SEQ ID NO 42) -RSYSSAFKVFFSKQQ-. (SEQ ID NO 43) An exemplary and preferred polypeptide in this embodiment has an amino acid residue sequence selected from the group consisting of: VSPIPEAVEVKDASQHPQM, and (SEQ ID NO 42) RSYSSAFKVFFSKQQ. (SEQ ID NO 43) In a related embodiment, a REC20 serotonin receptor polypeptide of the present invention has a length of no more than about 100 amino acid residueε, has an amino acid residue sequence that corresponds to the sequence of REC20 shown in SEQ ID NO 11, and includes an amino acid residue sequence represented by a formula selected from the group consisting of: -RKSAAKHKFPGFPRVQPES- , (SEQ ID NO 44) -PEVGRGLQDLSPDGGAHPWS-, and (SEQ ID NO 45) -SRLLKHERKNISIFKREQK-. (SEQ ID NO 46) An exemplary and preferred polypeptide in this embodiment has an amino acid residue sequence selected from the group consisting of: RKSAAKHKFPGFPRVQPES, (SEQ ID NO 44) PEVGRGLQDLSPDGGAHPWS, and (SEQ ID NO 45) SRLLKHERKNISIFKREQK. (SEQ ID NO 46) The invention also contemplates serotonin receptor polypeptides which are specifically designed for their capacity to mimic exposed regions of εerotonin receptor involved in serotonin receptor binding interactions and thereby receptor function. Therefore, these polypeptides have the capacity to function as analogs to the serotonin receptor, and thereby block function. In addition, these polypeptides corresponding to exposed domains have the ability to induce antibody molecules that immunoreact with a serotonin receptor of this invention at portions of the serotonin receptor involved in receptor protein function, and therefor the antibodies are also useful at modulating normal receptor function. Candidate polypeptides derived from exposed regions of a serotonin receptor are shown in Table 4, with the domain of the receptor being indicated also. For example, amino terminus region polypeptides are indicated by "N-terminus", extracellular loop structures are indicated by "EC loop #", and carboxy terminus region polypeptides are indicated by "C- terminus". Thus, the present invention also contemplates a serotonin receptor polypeptide that has a length of no more than about 100 amino acid residues, has an amino acid residue sequence that corresponds to the sequence of its corresponding serotonin receptor shown in the sequence listings, and includes an amino acid residue sequence represented by a formula εelected from the group conεisting of the polypeptides shown in Table 4. In this embodiment, the polypeptide iε further characterized as having the ability to mimic a serotonin receptor epitope and thereby inhibits receptor function in a classic receptor activation assay. Preferred exposed region polypeptides have the sequence shown in Table 4. Due to the three dimensional structure of a native folded serotonin receptor molecule, the present invention contemplates that multiple regions of protein serotonin receptor are involved in receptor function, which multiple and various regions are defined by the various serotonin receptor polypeptides described above. The ability of the above-described serotonin receptor polypeptides to inhibit receptor- ligand binding can readily be measured in a ligand binding assay as is shown in the Examples herein. Similarly, the ability of the above-described serotonin receptor polypeptides to inhibit receptor function can readily be measured in a receptor activation assay as is described herein. Thus, in another embodiment, the invention contemplates serotonin receptor polypeptide compositions that comprise one or more of the different serotonin receptor polypeptides described above which inhibit serotonin receptor function, admixed in combinations to provide simultaneous inhibition of multiple contact sites on the serotonin receptor. A subject polypeptide includes any analog, fragment or chemical derivative of a polypeptide whose amino acid residue sequence is shown herein so long as the polypeptide iε capable of mimicking an epitope of a serotonin receptor. Therefore, a present polypeptide can be subject to various changes, subεtitutionε, inεertionε, and deletions where such changes provide for certain advantages in its use. In this regard, a serotonin receptor polypeptide of this invention correεponds to, rather than is identical to, the sequence of a serotonin receptor where one or more changes are made and it retains the ability to induce antibodies that immunoreact with a serotonin receptor of thiε invention. The term "analog" includeε any polypeptide having an amino acid residue sequence substantially identical to a sequence specifically shown herein in which one or more residues have been conservatively substituted with a functionally similar residue and which displays the ability to induce antibody production as described herein. Examples of conservative substitutions include the substitution of one non-polar (hydrophobic) residue such as isoleucine, valine, leucine or methionine for another, the substitution of one polar (hydrophilic) residue for another such as between arginine and lysine, between glutamine and asparagine, between glycine and serine, the substitution of one basic residue such as lysine, arginine or histidine for another, or the substitution of one acidic residue, such as aspartic acid or glutamic acid for another. The phrase "conservative substitution" also includes the use of a chemically derivatized residue in place of a non-derivatized residue provided that such polypeptide displays the requisite binding activity. "Chemical derivative" refers to a subject polypeptide having one or more residues chemically derivatized by reaction of a functional side group. Such derivatized molecules include for example, those molecules in which free amino groups have been derivatized to form amine hydrochlorideε, p-toluene sulfonyl groups, carbobenzoxy groups, t- butyloxycarbonyl groups, chloroacetyl groups or formyl groups. Free carboxy1 groups may be derivatized to form salts, methyl and ethyl esters or other types of esters or hydrazideε. Free hydroxyl groups may be derivatized to form O-acyl or O-alkyl derivatives. The imidazole nitrogen of histidine may be derivatized to form N-im-benzylhiεtidine. Also included as chemical derivatives are those peptides which contain one or more naturally occurring amino acid derivativeε of the twenty standard amino acids. For exampleε: 4- hydroxyproline may be substituted for proline; 5- hydroxylysine may be substituted for lysine; 3- methylhistidine may be substituted for histidine; homoserine may be substituted for serine; and ornithine may be substituted for lysine. Polypeptides of the present invention also include any polypeptide having one or more additions and/or deletions or residues relative to the sequence of a polypeptide whose sequence is shown herein, so long as the requisite activity is maintained. The term "fragment" refers to any subject polypeptide having an amino acid residue sequence shorter than that of a polypeptide whose amino acid residue sequence is shown herein. When a polypeptide of the present invention has a sequence that iε not identical to the sequence of a serotonin receptor, it is typically because one or more conservative or non-conservative substitutions have been made, usually no more than about 30 number percent, more usually no more than 20 number percent, and preferably no more than 10 number percent of the amino acid residueε are substituted. Additional residues may also be added at either terminus for the purpose of providing a "linker" by which the polypeptides of this invention can be conveniently affixed to a label or solid matrix, or carrier. Preferably the linker residues do not form a serotonin receptor epitopeε, i.e., are not similar is structure to a serotonin receptor. Labels, solid matrices and carriers that can be used with the polypeptides of this invention are described hereinbelow. Amino acid residue linkers are usually at least one residue and can be 40 or more residues, more often 1 to 10 residues, but do not form a serotonin receptor epitopes. Typical amino acid residueε used for linking are tyrosine, cysteine, lysine, glutamic and aspartic acid, or the like. In addition, a subject polypeptide can differ, unless otherwise specified, from the natural sequence of a serotonin receptor by the sequence being modified by terminal-NH 2 acylation, e.g., acetylation, or thioglycolic acid amidation, by terminal-carboxylamidation, e.g., with ammonia, methylamine, and the like. When coupled to a carrier to form what is known in the art as a carrier-hapten conjugate, a serotonin receptor polypeptide of the present invention is capable of inducing antibodies that immunoreact with serotonin receptor. In view of the well established principle of immunologic cross-reactivity, the present invention therefore contemplates antigenically related variants of the polypeptides shown in Tables 3 and 4. An "antigenically related variant" is a subject polypeptide that is capable of inducing antibody molecules that immunoreact with a polypeptide from Tables 3 or 4 and with a serotonin receptor of this invention. Any peptide of the present invention may be used in the form of a pharmaceutically acceptable salt. Suitable acids which are capable of forming salts with the peptides of the present invention include inorganic acids such as hydrochloric acid, hydrobromic acid, perchloric acid, nitric acid, thiocyanic acid, sulfuric acid, phosphoric acetic acid, propionic acid, glycolic acid, lactic acid, pyruvic acid, oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, anthranilic acid, cinnamic acid, naphthalene sulfonic acid, sulfanilic acid or the like. Suitable bases capable of forming salts with the peptides of the present invention include inorganic bases such as sodium hydroxide, ammonium hydroxide, potassium hydroxide and the like; and organic bases such as mono-, di- and tri-alkyl and aryl amines (e.g. triethylamine, diisopropyl amine, methyl amine, dimethyl amine and the like) and optionally substituted ethanolamines (e.g. ethanolamine, diethanolamine and the like) . A serotonin receptor polypeptide of the present invention, also referred to herein as a subject polypeptide, can be synthesized by any of the techniques that are known to those skilled in the polypeptide art, including recombinant DNA techniques. Synthetic chemistry techniques, such as a solid-phase Merrifield-type synthesis, are preferred for reasons of purity, antigenic specificity, freedom from undesired side products, eaεe of production and the like. An excellent summary of the many techniques available can be found in J.M. Steward and J.D. Young, "Solid Phase Peptide Synthesis", W.H. Freeman Co., San Francisco, 1969; M. Bodanszky, et al., "Peptide Synthesis", John Wiley & Sons, Second Edition, 1976 and J. Meienhofer, "Hormonal Proteins and Peptides", Vol. 2, p. 46, Academic Presε (New York), 1983 for εolid phaεe peptide synthesis, and E. Schroder and K. Kubke, "The Peptides", Vol. 1, Academic Presε (New York) , 1965 for claεεical εolution synthesiε, each of which iε incorporated herein by reference. Appropriate protective groups usable in such synthesis are described in the above texts and in J.F.W. McOmie, "Protective Groups in Organic Chemistry", Plenum Press, New York, 1973, which is incorporated herein by reference. In general, the solid-phase synthesis methods contemplated comprise the sequential addition of one or more amino acid residueε or εuitably protected amino acid residues to a growing peptide chain. Normally, either the amino or carboxyl group of the first amino acid residue is protected by a suitable, selectively removable protecting group. A different, selectively removable protecting group is utilized for amino acids containing a reactive side group such as lysine. Using a solid phase synthesis as exemplary, the protected or derivatized amino acid is attached to an inert solid support through its unprotected carboxyl or amino group. The protecting group of the amino or carboxyl group is then selectively removed and the next amino acid in the sequence having the complimentary (amino or carboxyl) group suitably protected is admixed and reacted under conditions suitable for forming the amide linkage with the residue already attached to the solid support. The protecting group of the amino or carboxyl group is then removed from this newly added amino acid residue, and the next amino acid (suitably protected) is then added, and so forth. After all the desired amino acids have been linked in the proper sequence, any remaining terminal and side group protecting groups (and solid support) are removed sequentially or concurrently, to afford the final polypeptide. A serotonin receptor polypeptide can be used, inter alia, in the diagnostic methods and systems of the present invention to detect a serotonin receptor present in a body sample, or can be used to prepare an inoculum as described herein for the preparation of antibodies that immunoreact with conserved epitopes on a serotonin receptor. In addition, certain of the serotonin receptor polypeptides of thiε invention can be uεed in the therapeutic methodε of the present invention to inhibit serotonin receptor function as described further herein. G. Antibodies and Monoclonal Antibodies The term "antibody" in its various grammatical forms is used herein as a collective noun that refers to a population of immunoglobulin molecules and/or immunologically active portions of immunoglobulin molecules, i.e., molecules that contain an antibody combining site or paratope. An "antibody combining site" is that structural portion of an antibody molecule comprised of heavy and light chain variable and hypervariable regions that specifically binds antigen. The phrase "antibody molecule" in its variouε grammatical formε as used herein contemplates both an intact immunoglobulin molecule and an immunologically active portion of an immunoglobulin molecule. Exemplary antibody molecules for use in the diagnostic methods and systems of the present invention are intact immunoglobulin molecules, substantially intact immunoglobulin molecules and those portions of an immunoglobulin molecule that contain the paratope, including those portions known in the art as Fab, Fab', F(ab') 2 and F(v). Fab and F(ab') 2 portions of antibodies are prepared by the proteolytic reaction of papain and pepsin, respectively, on substantially intact antibodies by methods that are well known. See for example, U.S. Patent No. 4,342,566 to Theofilopolous and Dixon. Fab' antibody portions are also well known and are produced from F(ab') 2 portions followed by reduction of the diεulfide bondε linking the two heavy reduction of the disulfide bonds linking the two heavy chain portions as with mercaptoethanol, and followed by alkylation of the resulting protein mercaptan with a reagent such as iodoacetamide. An antibody containing intact antibody molecules are preferred, and are utilized as illustrative herein. An antibody of the present invention, i.e., an anti-serotonin receptor antibody, in one embodiment is characterized as comprising antibody molecules that immunoreact with a recombinant serotonin receptor of this invention. Preferably, an antibody further immunoreacts with a serotonin receptor polypeptide of the present invention. More preferably, an anti-serotonin receptor antibody is substantially free of the ability to immunoreact with other different εerotonin receptor proteins from other subfamilies. Thus a preferred antibody iε immunospecific for the serotonin receptor with which it immunoreacts, and can be used diagnostically to selectively detect the subfamily and type of serotonin receptor present in a tissue or body sample according to the diagnostic methods described further herein. By "substantially free" means that the antibody molecules do not immunoreact with the stated antigen at levels within one order of magnitude, and preferably within two orders of magnitude, of the level of immunoreaction with a species of antigen recited to immunoreact with the antibody molecule when immunoreaction is expressed as an equilibrium constant between bound (immunoreacted) and nonbound antigen. Thuε, the invention claimε an anti-serotonin receptor polypeptide antibody that immunoreacts with any of the serotonin receptor polypeptides of this invention, and also immunoreacts with the corresponding recombinant serotonin receptor protein. Preferably, and antibody is substantially free from immunoreaction with a serotonin receptor from a different subfamily or type. Asεayε for immunoreaction useful for asseεεing immunoreactivity are described herein. In one embodiment, antibody molecules are described that immunoreact with a serotonin receptor polypeptide of the present invention and that have the capacity to immunoreact with an exposed site on a serotonin receptor that iε required for serotonin receptor function. Thus, preferred antibody moleculeε in thiε embodiment alεo inhibit εerotonin receptor function, and are therefore useful therapeutically to block the receptor's function. Exemplary serotonin receptor inhibitory antibodies immunoreact with a serotonin receptor polypeptide described herein that defines an exposed region of a serotonin receptor that iε involved in εerotonin receptor function, such as ligand binding. An antibody of the present invention is typically produced by immunizing a mammal with an inoculum containing an serotonin receptor polypeptide of thiε invention and thereby induce in the mammal antibody moleculeε having i munoεpecificity for immunizing polypeptide. The antibody molecules are then collected from the mammal and iεolated to the extent desired by well known techniques such as, for example, by using DEAE Sephadex to obtain the IgG fraction. Exemplary antibody preparation methods using εerotonin receptor polypeptides in the immunogen are described herein in the Examples. The preparation of antibodies against polypeptide is well known in the art. See Staudt et al., J. Exp. Med.. 157:687-704 (1983), or the teachings of Sutcliffe, J.G., as described in United States Patent No. 4,900,811, the teaching of which are hereby incorporated by reference. Briefly, to produce a peptide antibody composition of this invention, a laboratory mammal iε inoculated with an immunologically effective amount of a serotonin receptor polypeptide, typically as present in a vaccine of the present invention. The anti- serotonin receptor polypeptide antibody molecules thereby induced are then collected from the mammal and those immunospecific for both the serotonin receptor polypeptide and the corresponding recombinant serotonin receptor are isolated to the extent desired by well known techniques such as, for example, by immunoaffinity chromatography. To enhance the specificity of the antibody, the antibodies are preferably purified by immunoaffinity chromatography using solid phase-affixed immunizing polypeptide. The antibody is contacted with the solid phase-affixed immunizing polypeptide for a period of time sufficient for the polypeptide to immunoreact with the antibody molecules to form a solid phase- affixed immunocomplex. The bound antibodies are separated from the complex by standard techniques. The word "inoculum" in its various grammatical formε iε used herein to describe a composition containing a serotonin receptor polypeptide of thiε invention as an active ingredient used for the preparation of antibodies against a serotonin receptor polypeptide. When a polypeptide iε uεed in an inoculum to induce antibodies it is to be understood that the polypeptide can be used in various embodiments, e.g., alone or linked to a carrier as a conjugate, or as a polypeptide polymer. However, for ease of expression and in context of a polypeptide inoculum, the variouε embodimentε of the polypeptideε of thiε invention are collectively referred to herein by the term "polypeptide" and its various grammatical forms. For a polypeptide that contains fewer than about 35 amino acid residues, it is preferable to use the peptide bound to a carrier for the purpose of inducing the production of antibodies. One or more additional amino acid residues can be added to the amino- or carboxy-termini of the polypeptide to assist in binding the polypeptide to a carrier. Cysteine residues added at the amino- or carboxy-termini of the polypeptide have been found to be particularly useful for forming conjugates via disulfide bonds. However, other methods well known in the art for preparing conjugates can also be used. The techniques of polypeptide conjugation or coupling through activated functional groups presently known in the art are particularly applicable. See, for example, Aurameas, et al., Scand. J. Immunol. f Vol. 8, Suppl. 7:7-23 (1978) and U.S. Patent No. 4,493,795, No. 3,791,932 and No. 3,839,153. In addition, a εite-directed coupling reaction can be carried out εo that any loεε of activity due to polypeptide orientation after coupling can be minimized. See, for example, Rodwell et al., Biotech.. 3:889-894 (1985), and U.S. Patent No. 4,671,958. Exemplary additional linking procedures include the use of Michael addition reaction products, di- aldehydeε εuch aε glutaraldehyde, Klipεtein, et al., J. Infect. Diε.. 147:318-326 (1983) and the like, or the use of carbodiimide technology as in the use of a water-soluble carbodiimide to form amide links to the carrier. Alternatively, the heterobifunctional cross- linker SPDP (N-succinimidyl-3-(2-pyridyldithio) proprionate) ) can be used to conjugate peptides, in which a carboxy-terminal cysteine has been introduced. Useful carriers are well known in the art, and are generally proteins themselves. Exemplary of such carriers are keyhole limpet hemocyanin (KLH) , edestin, thyroglobulin, albumins such as bovine serum albumin (BSA) or human serum albumin (HSA) , red blood cells such as sheep erythrocytes (SRBC) , tetanus toxoid, cholera toxoid as well as polyamino acids such as poly D-lysine:D-glutamic acid, and the like. The choice of carrier is more dependent upon the ultimate use of the inoculum and is based upon criteria not particularly involved in the present invention. For example, a carrier that does not generate an untoward reaction in the particular animal to be inoculated should be selected. The present inoculum contains an effective, immunogenic amount of a polypeptide of thiε invention, typically as a conjugate linked to a carrier. The effective amount of polypeptide per unit dose εufficient to induce an immune response to the immunizing polypeptide depends, among other things, on the species of animal inoculated, the body weight of the animal and the chosen inoculation regimen is well known in the art. Inocula typically contain polypeptide concentrations of about 10 micrograms (μg) to about 500 milligramε (mg) per inoculation (doεe) , preferably about 50 micrograms to about 50 milligramε per dose. The term "unit dose" as it pertains to the inocula refers to physically discrete units suitable as unitary dosages for animals, each unit containing a predetermined quantity of active material calculated to produce the desired immunogenic effect in association with the required diluent; i.e., carrier, or vehicle. The specifications for the novel unit dose of an inoculum of this invention are dictated by and are directly dependent on (a) the unique characteristics of the active material and the particular immunologic effect to be achieved, and (b) the limitations inherent in the art of compounding such active material for immunologic use in animals, as disclosed in detail herein, these being features of the present invention. Inocula are typically prepared from the dried solid polypeptide-conjugate by diεperεing the polypeptide-conjugate in a phyεiologically tolerable (acceptable) diluent such as water, saline or phosphate-buffered saline to form an aqueous composition. Inocula can also include an adjuvant as part of the diluent. Adjuvants such as complete Freund's adjuvant (CFA), incomplete Freund's adjuvant (IFA) and alum are materials well known in the art, and are available commercially from several sourceε. The antibody εo produced can be uεed, inter alia. in the diagnostic methods and systems of the present invention to detect a serotonin receptor present in a sample such as a tissue section or body fluid sample. Anti-serotonin receptor antibodies that inhibit serotonin receptor function can also be used .in vivo in therapeutic methods as described herein. A preferred anti-serotonin receptor antibody is a monoclonal antibody. The phrase "monoclonal antibody" in its various grammatical forms refers to a population of antibody molecules that contain only one species of antibody combining site capable of immunoreacting with a particular epitope. A monoclonal antibody thus typically displays a single binding affinity for any epitope with which it immunoreacts. A monoclonal antibody may therefore contain an antibody molecule having a plurality of antibody combining sites, each immunospecific for a different epitope, e.g., a bispecific monoclonal antibody. A preferred monoclonal antibody of this invention comprises antibody molecules that immunoreact with a 1) recombinant serotonin receptor, and 2) a serotonin receptor polypeptide of the present invention as described for the anti-serotonin receptor antibodieε of this invention. A monoclonal antibody is typically compoεed of antibodieε produced by cloneε of a εingle cell called a hybridoma that εecreteε (produceε) only one kind of antibody molecule. The hybridoma cell iε formed by fuεing an antibody-producing cell and a myeloma or other self-perpetuating cell line. The preparation of such antibodies was first described by Kohler and Milstein, Nature, 256:495-497 (1975) , the deεcription of which iε incorporated by reference. The hybridoma supernates εo prepared can be εcreened for the presence of antibody molecules that immunoreact with a serotonin receptor polypeptide, or for inhibition serotonin receptor function. Briefly, to form the hybridoma from which the monoclonal antibody composition is produced, a myeloma or other self-perpetuating cell line is fused with lymphocytes obtained from the εpleen of a mammal hyperimmunized with a serotonin receptor antigen, such as is present in a serotonin receptor polypeptide of this invention. The polypeptide-induced hybridoma technology is described by Niman et al., Proc. Natl. Acad. Sci.. USA. 80:4949-4953 (1983), the description of which is incorporated herein by reference. It is preferred that the myeloma cell line used to prepare a hybridoma be from the same species aε the lymphocytes. Typically, a mouse of the strain 129 G1X + is the preferred mammal. Suitable mouse myelomas for use in the present invention include the hypoxanthine-aminopterin-thymidine-senεitive (HAT) cell lines P3X63-Ag8.653, and Sp2/0-Agl4 that are available from the American Type Culture Collection, Rockville, MD, under the designationε CRL 1580 and CRL 1581, respectively. Splenocytes are typically fused with myeloma cells using polyethylene glycol (PEG) 1500. Fused hybrids are εelected by their sensitivity to HAT. Hybridomas producing a monoclonal antibody of this invention are identified using the enzyme linked immunosorbent asεay (ELISA) described in Example 4. A monoclonal antibody of the present invention can also be produced by initiating a monoclonal hybridoma culture comprising a nutrient medium containing a hybridoma that produceε and εecreteε antibody molecules of the appropriate polypeptide specificity. The culture is maintained under conditions and for a time period sufficient for the hybridoma to secrete the antibody molecules into the medium. The antibody-containing medium iε then collected. The antibody moleculeε can then be further isolated by well known techniques. Media useful for the preparation of these compositions are both well known in the art and commercially available and include synthetic culture media, inbred mice and the like. An exemplary synthetic medium is Dulbecco's Minimal Essential Medium (DMEM; Dulbecco et al., Virol. 8:396 (1959)) supplemented with 4.5 gm/1 glucose, 20 mm glutamine, and 20% fetal calf serum. An exemplary inbred mouse strain is the Balb/c. Other methods of producing a monoclonal antibody, a hybridoma cell, or a hybridoma cell culture are also well known. See, for example, the method of isolating monoclonal antibodies from an immunological repertoire as described by Sastry, et al., Proc. Natl. Acad. Sci. USA, 86:5728-5732 (1989); and Huse et al.. Science. 246:1275-1281 (1989). The monoclonal antibodieε of thiε invention can be used in the same manner as disclosed herein for antibodies of the present invention. For example, the monoclonal antibody can be used in the therapeutic, diagnostic or in vitro methods disclosed herein where immunoreaction with a serotonin receptor iε deεired. Alεo contemplated by this invention is the hybridoma cell, and cultures containing a hybridoma cell that produce a monoclonal antibody of this invention. H. Therapeutic Methods and Compositions 1. Therapeutic Methods It is contemplated that the certain reagents described in the present invention have the capacity to modulate serotonin receptor function, and therefore are useful in therapeutic methods for conditions mediated by the serotonin receptor. Serotonin receptor polypeptides that mimic exposed regions of a serotonin receptor have the ability to function as analogs and compete for binding to the natural ligand, or for other agents that would normally interact with the receptor, thereby inhibiting binding of that ligand/agent to the receptor. Furthermore, antibodies and monoclonal antibodies of the present invention that bind to exposed regions of a serotonin receptor of this invention have the capacity to alter serotonin receptor function by blocking natural interactions with ligand or other agents that normally interact at the site. Exemplary antibodies are the anti-serotonin receptor polypeptide antibodies described earlier that bind "exposed" serotonin receptor polypeptides. Finally, oligonucleotideε are deεcribed herein which are complementary to mRNA that encodes a εerotonin receptor of this invention and that are useful for reducing gene expreεεion and tranεlation of the serotonin receptor mRNA. Thus, in one embodiment, the present invention provides a method for modulating serotonin receptor function in a animal or human patient comprising administering to the patient a therapeutically effective amount of a physiologically tolerable composition containing a serotonin receptor polypeptide, anti-εerotonin receptor antibody or monoclonal antibody of the present invention. A therapeutically effective amount of a serotonin receptor polypeptide is a predetermined amount calculated to achieve the desired effect, i.e., to inhibit receptor interaction with its normal target, and thereby interfere with normal receptor function. Similarly, a therapeutically effective amount of an anti-serotonin receptor antibody is a predetermined amount calculated to achieve the deεired effect, i.e., to immunoreact with the receptor, and thereby inhibit the receptor's ability to interaction with its normal target, and thereby interfere with normal receptor function. The in vivo inhibition of a serotonin receptor function using a serotonin receptor polypeptide or anti-serotonin receptor antibody of this invention is a particularly preferred embodiment and is desirable in a variety of clinical settings, such as where the patient is exhibiting symptoms of an over or under activated serotonin receptor. A therapeutically effective amount of a serotonin receptor polypeptide of this invention is typically an amount of serotonin receptor polypeptide such that when administered in a physiologically tolerable composition is sufficient to achieve a plasma concentration of from about 0.1 micromolar (μM) to about 100 μM, and preferably from about 0.5 μM to about 10 μM. A therapeutically effective amount of an antibody of this invention is typically an amount of antibody such that when administered in a physiologically tolerable composition is sufficient to achieve a plasma concentration of from about 0.1 microgram (μg) per milliliter (ml) to about 100 μg/ml, preferably from about 1 μg/ml to about 5 μg/ml, and usually about 5 μg/ml. The effectiveness of the therapy can be determined by observing ablation of the symptomε associated with the function of the serotonin receptor being inhibited. The therapeutic compositions containing a serotonin receptor polypeptide or anti-serotonin receptor antibody of this invention are conventionally administered intravenously, as by injection of a unit dose, for example. The term "unit dose" when used in reference to a therapeutic composition of the present invention refers to physically discrete units suitable as unitary dosage for the subject, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect in association with the required diluent; i.e., carrier, or vehicle. The compositions are administered in a manner compatible with the dosage formulation, and in a therapeutically effective amount. The quantity to be administered depends on the subject to be treated, capacity of the subject's system to utilize the active ingredient, and degree of therapeutic effect desired. Precise amounts of active ingredient required to be administered depend on the judgement of the practitioner and are particular to each individual. However, suitable dosage ranges for systemic application arc discloεed herein and depend on the route of administration. Suitable regimes for initial administration and booster εhotε are alεo variable, but are typified by an initial adminiεtration followed by repeated doεeε at one or more hour intervalε by a subsequent injection or other administration. Alternatively, continuous intravenous infuεion εufficient to maintain concentrationε in the blood in the rangeε specified for in vivo therapies are contemplated. As an aid to the administration of effective therapeutic amounts of a serotonin receptor polypeptide, antibody, or monoclonal antibody, a diagnostic method of this invention for detecting a serotonin receptor polypeptide, antibody, or monoclonal antibody, respectively, in the subject's blood is useful to characterize the fate of the administered therapeutic composition. Suitable diagnostic (monitoring) asεayε are deεcribed herein. 2. Methodε for Inhibiting Gene Expreεεion In another embodiment, the invention contemplates the use of nucleic acids encoding portions of a serotonin receptor gene for inhibiting gene expression and function. Thus, the present invention provides for a method for inhibiting expression of serotonin receptor gene products and thereby inhibiting the function of the target serotonin receptor. The DNA segments and their compositions ave a number of useε, and may be used in vitro or in vivo. In vitro, the compositionε may be used to block function and/or expression of serotonin receptor in cell cultures, tisεueε, organε and the like materialε that can expreεε εerotonin receptor. In vivo, the compositions may be used prophylactically or therapeutically for inhibiting expresεion of a εerotonin receptor gene, and by inhibiting diεeaεeε aεεociated with the expression of the serotonin receptor gene. The method comprises, in one embodiment, contacting human cellε with a therapeutically effective amount of a pharmaceutically acceptable composition comprising a DNA segment of this invention. In a related embodiment, the contacting involves introducing the DNA segment composition into cellε having a εerotonin receptor. The DNA segment can be in a variety of forms, but iε preferably in a single-stranded form to facilitate complementary hybridization to the target mRNA in the cell in which the serotonin receptor gene expresεion iε to be altered. The term "cellε" is intended to include a plurality of cells as well aε εingle cellε. The cellε can be isolated, or can be cells that form a larger organization of cells to form a tissue or organ. In a further embodiment, the invention contemplated the method of inhibiting the expresεion of serotonin receptor genes in a patient comprising administration to the patient of a therapeutically effective amount of a DNA segment composition of this invention in a pharmaceutically acceptable excipient. In caseε where the distribution of the serotonin receptor iε believed to be diεεeminated in the body, the adminiεtration of therapeutic oligonucleotide can be systemic. Alternatively, the target serotonin receptor can be localized to a tissue, and the therapeutic method can likewise be directed at delivering the therapeutic DNA segment to the tissue to be treated. The therapeutic compounds and compositions are generally administered so aε to contact the cellε or the tissue containing cells which contain the target serotonin receptor. This administration can be accomplished by introduction of the composition internally such as orally, intravenouεly, intramuscularly, intranasally or via inhalation of aerosols containing the composition, and the like, or by introduction into or onto a tissue system as by introduction transdermally, topically or intralesionally, in suppositories, or by intra-orbital injection, and the like. The concentration of the active DNA segment ingredient in a therapeutic composition will vary, depending upon the desired dosage, use, frequency of administration, and the like. The amount used will be a therapeutically effective amount and will depend upon a number of factors, including the route of administration, the formulation of the composition, the number and frequency of treatments and the activity of the formulation employed. The use of therapeutic DNA segments, and therefore the delivery of those DNA segments into cells where they are effective, has been described in a variety of settings. It is generally known that therapeutically effective intracellular levels of nucleic acids, and particularly smaller nucleic acids such as DNA segments and oligonucleotides, can be achieved by either exposing cells to solutions containing nucleic acids or by introduction of the nucleic acids into the inside of the cell. Upon exposure, nucleic acids are taken up by the cell where they exert their effectiveness. In addition, direct introduction into the cell can be provided by a variety of means, including microinjection, delivery by the use of specific uptake vehicles, and the like. The pharmaceutical composition containing the therapeutic oligonucleotide preferably also contains physiologically acceptable carriers, in particular hydrophobic carriers which facilitate carrying the oligonucleotide through the cell membrane. Exemplary descriptionε of the delivery of therapeutic DNA εegmentε and oligonucleotideε into cellε can be found in the teachingε of United Stateε Patent Noε. 5,04,820, 4,806,463, 4,757,055, and 4,689,320, which teachings are hereby incorporated by reference. A therapeutically effective amount is a predetermined amount calculated to achieve the desired effect, i.e., to bind to a serotonin receptor gene present and thereby inhibit function of the gene. As is apparent to one skilled in the art, the copy number of a serotonin receptor gene may vary, thereby presenting a variable amount of target with which to hybridize. Thus it is preferred that the therapeutic method achieve an intracellular concentration of a therapeutic DNA segment of this invention in molar excesε to the copy number of the gene in the cell, and preferably at leaεt a ten-fold, more preferably at least a one-hundred fold, and still more preferably at least a one thousand-fold excesε of therapeutic DNA εegmentε relative to the gene copy number per cell. A preferred effective amount iε an intracellular concentration of from about 1 nanomolar (nM) to about 100 micromolar (μM) , particularly about 50 nM to about 1 μM. Alternatively, a therapeutically effective amount can be expreεεed as an extracellular concentration. Thus it iε preferred to expose an cell containing a εerotonin receptor gene to a concentration of from about 100 nM to about 10 millimolar (mM) , and preferably about 10 μM to 1 mM. Thuε, in embodimentε where delivery of a therapeutic DNA segment composition is designed to expose cells to the nucleic acid for cellular uptake, it is preferred that the local concentration of the DNA segment in the area of the tissue to be treated reach the extracellular concentrations recited above. For patient dosages, using a 20 nucleotide base double-εtranded DNA segment as the standard, a typical dosage of therapeutic composition for a 70 kilogram (kg) human contains in the range of about 0.1 milligram (mg) to about 1 gram of 20-mer DNA segment per day, and more usually in the range of about 1 mg to 100 mg per day. Stated differently, a dosage of about 1 μg/kg/g day to about 15 mg/kg/day, and preferably about 15 to 1500 μg/kg/day is contemplated. The in vivo inhibition of serotonin receptor gene expression and/or function by a therapeutic composition of this invention is desirable in a variety of clinical settingε, such as where the patient is at risk for disease based on expression of the serotonin receptor gene. The disease depends on the particular serotonin receptor and the physiological role that receptor plays in the subject patient. Serotonin receptors are known to participate in a variety of neurological processeε and pathologieε including dementia, Parkinson's disease, eating disorderε, pathological anxiety, migraine headacheε, inεomnia and other conditionε. In view of the evidence herein that the serotonin receptor 5-HT 6 (REC20) participates in managing circadian rhythms of the superchiasmatic nucleus, the therapeutic reagents described herein specific for REC20 are particularly suited to therapeutic methods for altering the phase of the circadian rhythm clock in a mammal. Therefor, the invention contemplates a method for altering the circadian rhythm phasing of a mammal, or treating any disorder aεεociated with phasing of the clock, comprising administering a therapeutic composition of this invention specific for REC20 in an amount sufficient to inhibit REC20 serotonin receptor function. 3. Therapeutic Compositionε The present invention contemplates therapeutic compositionε uεeful for practicing the therapeutic methods described herein. Therapeutic compositions of the present invention contain a physiologically tolerable carrier together with a therapeutic reagent of this invention, namely a serotonin receptor polypeptide, an anti-serotonin receptor antibody or monoclonal antibody, or oligonucleotide as described herein, dissolved or dispersed therein as an active ingredient. In a preferred embodiment, the therapeutic composition iε not immunogenic when administered to a mammal or human patient for therapeutic purposeε. Aε uεed herein, the termε "pharmaceutically acceptable", "phyεiologically tolerable" and grammatical variationε thereof, aε they refer to compoεitionε, carrierε, diluentε and reagentε, are used interchangeably and repreεent that the materialε are capable of adminiεtration to or upon a mammal without the production of undeεirable phyεiological effectε such aε nausea, dizzinesε, gaεtric upset and the like. The preparation of a pharmacological composition that contains active ingredients disεolved or dispersed therein is well understood in the art. Typically such compositions are prepared aε injectables either as liquid solutions or suspensions, however, solid forms suitable for solution, or suspensions, in liquid prior to use can also be prepared. The preparation can also be emulsified. The active ingredient can be mixed with excipients which are pharmaceutically acceptable and compatible with the active ingredient and in amountε suitable for use in the therapeutic methods described herein. Suitable excipients are, for example, water, saline, dextrose, glycerol, ethanol or the like and combinations thereof. In addition, if desired, the composition can contain minor amounts of auxiliary substances such as wetting or emulsifying agents, pH buffering agents and the like which enhance the effectiveness of the active ingredient. The therapeutic composition of the present invention can include pharmaceutically acceptable salts of the components therein. Pharmaceutically acceptable salts include the acid addition salts (formed with the free amino groups of the polypeptide) that are formed with inorganic acids such as, for example, hydrochloric or phosphoric acids, or such organic acids as acetic, tartaric, mandelic and the like. Salts formed with the free carboxyl groups can also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium or ferric hydroxides, and such organic baseε as isopropylamine, trimethylamine, 2-ethylamino ethanol, hiεtidine, procaine and the like. Phyεiologically tolerable carrierε are well known in the art. Exemplary of liquid carrierε are εterile aqueouε εolutionε that contain no materialε in addition to the active ingredients and water, or contain a buffer such as sodium phosphate at phyεiological pH value, physiological saline or both, such as phoεphate-buffered εaline. Still further, aqueous carriers can contain more than one buffer salt, as well aε salts such as sodium and potassium chlorides, dextrose, polyethylene glycol and other solutes. As described herein, for intracellular delivery of oligonucleotides, specialized carriers may be used which facilitate transport of the oligonucleotide across the cell membrane. These typically are hydrophobic compoεitionε, or include additional reagents which target delivery to and/or into cells. Liquid compositions can also contain liquid phases in addition to and to the exclusion of water. Exemplary of such additional liquid phases are glycerin, vegetable oils such as cottonseed oil, and water-oil emulsions. A therapeutic composition contains an amount of a serotonin receptor polypeptide or anti-serotonin receptor antibody molecule of the present invention sufficient to inhibit serotonin receptor function. Typically this is an amount of at least 0.1 weight percent, and more preferably is at leaεt 1 weight percent, of peptide or antibody per weight of total therapeutic compoεition. A weight percent iε a ratio by weight of peptide or antibody to total composition. Thus, for example, 0.1 weight percent iε 0.1 grams of polypeptide per 100 grams of total compoεition. I. Diagnostic Systems and Methods 1. Diagnostic Svεtemε The present invention also describeε a diagnostic system, preferably in kit form, for assaying for the presence of a serotonin receptor of this invention in a body sample, such brain tissue, cell suspensions or tissue sections, or body fluid samples such as blood, plasma or serum, where it is desirable to detect the presence, and preferably the amount, of a serotonin receptor in the sample according to the diagnostic methods described herein. In a related embodiment, a nucleic acid molecule can be used as a probe (an oligonucleotide) to detect the presence of a gene or mRNA in a cell that is diagnostic for the presence or expression of a serotonin receptor gene in the cell. The nucleic acid molecule probes were described in detail earlier. The diagnostic system includes, in an amount sufficient to perform at least one assay, a subject serotonin receptor polypeptide, a subject antibody or monoclonal antibody, and/or a subject nucleic acid molecule probe of the present invention, as a separately packaged reagent. In another embodiment, a diagnostic system, preferably in kit form, is contemplated for assaying for the presence of a serotonin receptor polypeptide or anti-serotonin receptor antibody in a body fluid sample such as for monitoring the fate of therapeutically administered serotonin receptor polypeptide or anti-serotonin receptor antibody. The system includes, in an amount sufficient for at least one assay, a subject serotonin receptor polypeptide and/or a subject antibody as a separately packaged immunochemical reagent. Instructions for use of the packaged reagent(ε) are alεo typically included. As used herein, the term "package" refers to a εolid matrix or material such as glass, plastic (e.g., polyethylene, polypropylene or polycarbonate) , paper, foil and the like capable of holding within fixed limits a polypeptide, polyclonal antibody or monoclonal antibody of the present invention. Thus, for example, a package can be a glasε vial uεed to contain milligram quantitieε of a contemplated polypeptide or antibody or it can be a microtiter plate well to which microgram quantitieε of a contemplated polypeptide or antibody have been operatively affixed, i.e., linked so as to be capable of being immunologically bound by an antibody or antigen, respectively. "Instructions for use" typically include a tangible expression describing the reagent concentration or at least one assay method parameter such as the relative amounts of reagent and sample to be admixed, maintenance time periods for reagent/ sample admixtures, temperature, buffer conditions and the like. A diagnostic system of the present invention preferably also includes a label or indicating means capable of signaling the formation of an immunocomplex containing a polypeptide or antibody molecule of the present invention. The word "complex" as used herein refers to the product of a specific binding reaction such as an antibody-antigen or receptor-ligand reaction. Exemplary complexes are immunoreaction products. As used herein, the terms "label" and "indicating means" in their various grammatical formε refer to εingle atomε and moleculeε that are either directly or indirectly involved in the production of a detectable εignal to indicate the presence of a complex. Any label or indicating meanε can be linked to or incorporated in an expressed protein, polypeptide, or antibody molecule that is part of an antibody or monoclonal antibody composition of the present invention, or used separately, and those atoms or molecules can be used alone or in conjunction with additional reagentε. Such labels are themselveε well- known in clinical diagnostic chemistry and constitute a part of this invention only insofar as they are utilized with otherwise novel proteins methods and/or systems. The labeling means can be a fluorescent labeling agent that chemically binds to antibodies or antigens without denaturing them to form a fluorochrome (dye) that is a useful immunofluorescent tracer. Suitable fluorescent labeling agents are fluorochromes such as fluorescein isocyanate (FIC) , fluorescein isothiocyante (FITC) , 5-dimethylamine-l- naphthalenesulfonyl chloride (DANSC) , tetramethylrhoda ine isothiocyanate (TRITC) , lissamine, rhodamine 8200 sulphonyl chloride (RB 200 SC) and the like. A description of immunofluorescence analysis techniques is found in DeLuca, "Immunofluorescence Analysis", in Antibody As a Tool. Marchalonis, et al., eds. , John Wiley & Sons, Ltd., pp. 189-231 (1982), which is incorporated herein by reference. In preferred embodiments, the indicating group is an enzyme, such as horseradiεh peroxidaεe (HRP) , glucose oxidase, or the like. In such cases where the principal indicating group is an enzyme such as HRP or glucoεe oxidaεe, additional reagents are required to visualize the fact that a receptor-ligand complex (immunoreactant) has formed. Such additional reagentε for HRP include hydrogen peroxide and an oxidation dye precursor such as diaminobenzidine. An additional reagent useful with glucose oxidase iε 2,2 '-amino-di- (3-ethyl-benzthiazoline-G-sulfonic acid) (ABTS) . Radioactive elements are alεo uεeful labeling agentε and are uεed illuεtratively herein. An exemplary radiolabeling agent is a radioactive element that produces gamma ray emisεionε. Elementε which themselves emit gamma rays, such aε 1 A I, 125 I, 128 I, 132 I and 51 Cr repreεent one claεε of gamma ray emiεsion- producing radioactive element indicating groups. Particularly preferred is 15 I. Another group of useful labeling means are those elements such aε 11 C, 18 F, 15 0 and 13 N which themselves emit positronε. The positrons so emitted produce gamma rays upon encounters with electrons present in the animal•s body. Also useful is a beta emitter, such 111 indium or 3 H. The linking of labels, i.e., labeling of, polypeptides and proteins is well known in the art. For instance, antibody molecules produced by a hybridoma can be labeled by metabolic incorporation of radioisotope-containing amino acidε provided aε a component in the culture medium. See, for example, Galfre et al., Meth. Enzvmol.. 73:3-46 (1981). The techniqueε of protein conjugation or coupling through activated functional groups are particularly applicable. See, for example, Aurameas, et al., Scand. J. Immunol.. Vol. 8 Suppl. 7:7-23 (1978), Rodwell et al., Biotech.. 3:889-894 (1984), and U.S. Pat. No. 4,493,795. The diagnostic εyεtemε can alεo include, preferably aε a εeparate package, a εpecific binding agent. A "εpecific binding agent" iε a molecular entity capable of selectively binding a reagent species of the present invention or a complex containing such a species, but is not itself a polypeptide or antibody molecule composition of the present invention. Exemplary specific binding agents are second antibody molecules, complement proteins or fragments thereof, S. aureus protein A, and the like. Preferably the εpecific binding agent binds the reagent species when that species is present as part of a complex. In preferred embodiments, the specific binding agent is labeled. However, when the diagnostic system includes a specific binding agent that is not labeled, the agent is typically used as an amplifying means or reagent. In these embodiments, the labeled specific binding agent is capable of specifically binding the amplifying means when the amplifying means is bound to a reagent species-containing complex. The diagnostic kits of the present invention can be used in an "ELISA" format to detect the quantity of a serotonin receptor in a sample. "ELISA" refers to an enzyme-linked immunosorbent assay that employs an antibody or antigen bound to a solid phase and an enzyme-antigen or enzyme-antibody conjugate to detect and quantify the amount of an antigen present in a sample. A description of the ELISA technique is found in Chapter 22 of the 4th Edition of Basic and Clinical Immunology by D.P. Sites et al., publiεhed by Lange Medical Publicationε of Loε Altoε, CA in 1982 and in U.S. Patentε No. 3,654,090; No. 3,850,752; and No. 4,016,043, which are all incorporated herein by reference. Thuε, in some embodiments, a serotonin receptor polypeptide, an antibody or a monoclonal antibody of the present invention can be affixed to a solid matrix to form a solid support that comprises a package in the subject diagnostic systems. A reagent is typically affixed to a solid matrix by adsorption from an aqueous medium although other modes of affixation applicable to proteinε and polypeptides can be used that are well known to thoεe εkilled in the art. Exemplary adεorption methodε are deεcribed herein. Uεeful solid matrices are also well known in the art. Such materials are water insoluble and include the cross-linked dextran available under the trademark SEPHADEX from Pharmacia Fine Chemicals (Piscataway, NJ) ; agarose; beads of polyεtyrene beadε about 1 micron (μ) to about 5 illimeterε (mm) in diameter available from Abbott Laboratorieε of North Chicago, IL; polyvinyl chloride, polyεtyrene, croεε-linked polyacrylamide, nitrocelluloεe- or nylon-based webs such as sheets, strips or paddles; or tubes, plates or the wells of a microtiter plate such as those made from polystyrene or polyvinylchloride. The reagent species, labeled specific binding agent or amplifying reagent of any diagnostic system described herein can be provided in solution, as a liquid dispersion or aε a εubεtantially dry power, e.g., in lyophilized form. Where the indicating meanε is an enzyme, the enzyme's subεtrate can also be provided in a separate package of a syεtem. A εolid εupport εuch aε the before-described microtiter plate and one or more buffers can alεo be included aε εeparately packaged ele entε in thiε diagnoεtic aεεay εyεtem. The packaging materialε diεcuεεed herein in relation to diagnoεtic εyεtems are those customarily utilized in diagnostic systems. 2. Diagnostic Methods The present invention contemplates various assay methods for determining the presence, and preferably amount, of a serotonin receptor in a body sample such as a tissue sample, including tissue mass or section, or a biological fluid sample using a polypeptide, polyclonal antibody or monoclonal antibody of this invention as an immunochemical reagent to form an immunoreaction product whose amount relates, either directly or indirectly, to the amount of a serotonin receptor in the sample. Those skilled in the art will understand that there are numerous well known clinical diagnostic chemistry procedures in which an immunochemical reagent of this invention can be used to form an immunoreaction product whose amount relates to the amount of serotonin receptor in a body sample. Thus, while exemplary assay methods are described herein, the invention is not so limited. Additionally, one can use the nucleic acid molecule probes described herein to detect the presence in a cell or tissue of a serotonin receptor gene or expressed gene in the form of mRNA encoding a serotonin receptor of this invention, as described further herein. Suitable probe-based assays are described in Sutcliffe, United States Patent No. 4,900,811, the disclosures of which are incorporated by reference. Various heterogenous and homogeneouε protocolε, either competitive or noncompetitive, can be employed in performing an aεsay method of this invention. For example, one embodiment contemplates a method for assaying the amount of serotonin receptor in a sample that utilizes an anti-serotonin receptor antibody to immunoreact with a serotonin receptor in a sample. In this embodiment, the antibody immunoreacts with a serotonin receptor to form a serotonin receptor-antibody immunoreaction complex, and the complex is detected indicating the presence of a serotonin receptor. An immunoassay method using an anti-serotonin receptor antibody molecule for assaying the amount of εerotonin receptor in a sample typically compriseε the steps of: (a) Forming an immunoreaction admixture by admixing a sample with an anti-serotonin receptor antibody of the present invention, preferably a monoclonal antibody. The sample is typically in the form of a fixed tissue section in a solid phase such that the immunoreaction admixture has both a liquid phaεe and a solid phase, and the antibody functions as a detection reagent for the presence of a serotonin receptor in the sample. Preferably, the sample is a brain tissue sample that has been prepared for immunohistological staining as is well known, although other tisεue samples may be adsorbed onto a solid phase, including tissue extracts or body fluid. In that case the adsorption onto a solid phase can be conducted aε deεcribed for well known Weεtern blot procedureε. (b) The immunoreaction admixture iε maintained under biological aεεay conditionε for a predetermined time period εuch aε about 10 minuteε to about 16-20 hourε at a temperature of about 4°C to about 45°C that, εuch time being εufficient for the εerotonin receptor present in the sample in the solid phase to immunoreact with (immunologically bind) the antibody and form a serotonin receptor-containing immunoreaction product (immunocomplex) in the solid phase. Biological assay conditions are those that maintain the biological activity of the immunochemical reagents of this invention and the serotonin receptor sought to be asεayed. Thoεe conditionε include a temperature range of about 4°C to about 45°C, a pH value range of about 5 to about 9 and an ionic strength varying from that of distilled water to that of about one molar sodium chloride. Methods for optimizing such conditions are well known in the art. (c) The amount of serotonin receptor-containing immunoreaction product that formed in step (b) is determined, thereby determining the amount of serotonin receptor present in the sample. Determining the amount of the immunoreaction product, either directly or indirectly, can be accomplished by assay techniques well known in the art, and typically depend on the type of indicating means used. Preferably, the determining of step (c) compriseε the steps of: (i) admixing the serotonin receptor- containing immunoreaction product in the εolid phase with a second antibody to form a second immunoreaction admixture having a liquid phase and a solid phase, said second antibody molecule having the capacity to immunoreact with the first antibody (primary) in the solid phase immunoreaction product. Antibodies useful aε the second antibody include polyclonal or monoclonal antibody preparations raised against the primary antibody. (ii) maintaining said second immunoreaction admixture for a time period sufficient for said second antibody to complex with the immunoreaction product and form a second immunoreaction product in the solid phase, and (iii) determining the amount of second antibody present in the second immunoreaction product and thereby the amount of immunoreaction product formed in step (c) . In one embodiment, the second antibody iε a labelled antibody such that the label provides an indicating means to detect the presence of the second immunoreaction product formed. The label is measured in the second immunoreaction product, thereby indicating the presence, and preferably amount, of second antibody in the solid phase. Alternatively, the amount of second antibody can be determined by preparation of an additional reaction admixture having an indicating means that specifically reacts with (bindε to) the εecond antibody, aε iε well known. Exemplary are third immunoreaction admixtureε with a labelled anti-immunoglobulin antibody molecule εpecific for the εecond antibody. After third immunoreaction, the formed third immunoreaction product is detected through the preεence of the label. Exemplary methods involve the use of in situ immunoreaction methods using tissue sectionε, or Weεtern blot procedureε, aε deεcribed by Sutcliffe in United Stateε Patent No. 4,900,811. Another embodiment iε contemplated for aεεaying the amount of therapeutically administered εerotonin receptor polypeptide or anti-εerotonin receptor antibody in a body fluid εa ple εuch aε blood, plaεma or serum. The method utilizes a competition reaction in which either a serotonin receptor polypeptide or an anti-serotonin receptor antibody molecule of thiε invention is present in the solid phase as an immobilized immunochemical reagent, and the other of the two reagents iε present in solution in the liquid phase, in the form of a labeled reagent. A fluid sample is admixed thereto to form a competition immunoreaction admixture, and the resulting amount of label in the solid phase is proportional, either directly or indirectly, to the amount of εerotonin receptor polypeptide or antibody in the fluid sample, depending upon the format. Thus one version of this embodiment comprises the steps of: (a) Forming a competition immunoreaction admixture by admixing a vascular fluid sample with: (1) an anti-serotonin receptor antibody according to this invention containing antibody molecules that immunoreact with a serotonin receptor, said antibody being operatively linked to a solid matrix such that the competition immunoreaction admixture has both a liquid phase and a solid phaεe, and (2) a polypeptide or recombinant εerotonin receptor protein of the present invention that is immunoreactive with the added antibody. The admixed polypeptide/protein in the liquid phase (labeled competing antigen) is operatively linked to an indicating means as described herein. (b) The competition immunoreaction admixture is then maintained for a time period sufficient for the competing antigen and the body sample antigen present in the liquid phase to compete for immunoreaction with the solid phaεe antibody. Such immunoreaction conditions are previously described, and result in the formation of an indicating means-containing immunoreaction product comprising the labeled competing antigen in the solid phase. (c) The amount of indicating means present in the product formed in step (b) is then determined, thereby determining the presence, and preferably amount, of sample antigen present in the vascular fluid sample. Determining the indicating means in the solid phase is then conducted by the standard methods described herein. A reverse version of this embodiment comprises the steps of: (a) Forming a competition immunoreaction admixture by admixing a vascular fluid sample with: (1) an anti-serotonin receptor antibody according to the preεent invention; and (2) a εerotonin receptor polypeptide or recombinant serotonin receptor of the present invention (capture antigen) that is immunoreactive with the antibody and iε operatively linked to a solid matrix such that the competition immunoreaction admixture has both a liquid phase and a solid phaεe. (b) The competition immunoreaction admixture iε then maintained for a time period εufficient for any εerotonin receptor antigen or anti- εerotonin receptor antibody in the vaεcular fluid to compete with the admixed antibody moleculeε for immunoreaction with the εolid phaεe capture antigen and form an antibody-containing immunoreaction product in the εolid phaεe. (c) The amount of antibody preεent in the product formed in step (b) is then determined, thereby determining the presence and/or amount of target material in the vascular fluid sample. In preferred embodiments, the antibody is operatively linked to an indicating means such that the determining in step (c) comprises determining the amount of indicating meanε preεent in the product formed in step (b) . Preferably, the vascular fluid sample is provided to a competition immunoreaction admixture as a known amount of blood, or a blood derived product such as serum or plasma. Further preferred are embodiments wherein the amount of immunochemical reagent in the liquid phase of the immunoreaction admixture is an excess amount relative to the amount of reagent in the solid phase. Typically, a parallel set of competition immunoreactions are established using a known amount of purified recombinant serotonin receptor or polypeptide in a dilution series so that a standard curve can be developed, as is well known. Thus, the amount of product formed in step (c) when using a vascular fluid sample is compared to the standard curve, thereby determining the amount of target antigen present in the vascular fluid. In another embodiment, the method for assaying the amount of serotonin receptor in a sample utilizes a first capture antibody to capture and immobilize serotonin receptor in the solid phase and a second indicator antibody to indicate the presence of the captured serotonin receptor antigen. In this embodiment, one antibody immunoreacts with a serotonin receptor to form a serotonin receptor-antibody immunoreaction complex, and the other antibody is able to immunoreact with the serotonin receptor while present in the serotonin receptor-antibody immunoreaction complex. This embodiment can be practiced in two formats with the immobilized capture antibody being either of the two above-identified antibodieε, and the indicator antibody being the other of the two antibodieε. Where a antibody iε in the solid phase as a capture reagent, a preferred means for determining the amount of solid phase reaction product is by the use of a labeled serotonin receptor polypeptide, followed by the detection meanε deεcribed herein for other labeled productε in the solid phase. Also contemplated are immunological asεayε capable of detecting the presence of immunoreaction product formation without the use of a label. Such methods employ a "detection means", which means are themselves well-known in clinical diagnostic chemistry and constitute a part of this invention only insofar aε they are utilized with otherwiεe novel polypeptideε, methodε and systemε. Exemplary detection meanε include methods known as biosenεorε and include bioεenεing methodε based on detecting changes in the reflectivity of a surface, changes in the absorption of an evanescent wave by optical fiberε or changeε in the propagation of εurface acouεtical waves. J. Transgenic Animalε In another embodiment, the present invention describeε provideε tranεgenic non-human animalε. The tranεgenic animal can have a exogenouε εerotonin receptor of thiε invention due to the presence of a gene encoding and expressing that receptor. By "exogenous" is meant that the animal harbors a gene derived from a different species. Preferably, the transgenic animal harbors a gene that encodes a human εerotonin receptor of this invention, and is useful as a model for human serotonin receptor function. Alternatively, a transgenic animal can have a mutation in a particular member of its own native serotonin receptor subfamily, thereby rendering the native receptor non-functional (i.e., a "knockout" transgenic animal) . Such an animal is useful as it presents the clinical conditions associated with the defects in the mutated serotonin receptor, and further can be a model for evaluation of candidate therapeutics that would treat subjects with defects in that serotonin receptor. Still further, a transgenic animal may be a knockout animal for a preselected serotonin receptor, and further contain an exogenous gene that encodes a homolog of the defective serotonin receptor derived from a different species, such as a human. Such a transgenic animal has a reconstituted serotonin receptor and thereby provides a model for studying the function of the homolog. Particularly preferred is a transgenic animal which contains a human εerotonin receptor of thiε invention in place of the corresponding native serotonin receptor. Such transgenic animals are useful as models to screen for therapeutic reagents that activate or inhibit the serotonin receptor function, and as models for evaluating efficacy or toxicity of a candidate therapeutic. Transgenic animalε are generally well known, aε iε their methodε of production. Thoεe methodε necessarily depend having a cloned gene of interest to transfer, or to mutate, as the case may be. In accordance with this invention, at least one copy of at least one serotonin receptor gene of this invention iε introduced into cells of a non-human animal. Preferably, subεtantially all of the cellε of the animal will contain the tranεgene. Thuε, the preεent invention contemplates a non- human animal containing a serotonin receptor gene of the present invention integrated in the genome of the animal's somatic and germ cells, i.e., a transgenic animal. Particularly preferred are transgenic mammals, and are utilized as exemplary herein. Animals containing a transgene encoding a serotonin receptor of the present invention are typically prepared using the standard transgenic technology described in Hogan et al, Manipulating the Mouse Embryo: A Laboratory Manual. Cold Spring Harbor, NY (1987) ; and Palmiter et al, Ann. Rev. Genet.. 20:465-499 (1986); which methodε are described further herein. Production of transgenic mammals is also posεible uεing the homologous recombination transgenic syεtemε deεcribed by Capecchi, Science. 244:288-292 (1989) . Preparation of tranεgenic mammals has also been deεcribed in U.S. Patent No. 4,736,866, No. 4,870,009, No. 4,873,191 and No. 4,873,316. One technique for tranεgenically altering a mammal iε to microinject a rDNA into the male pronucleus of the fertilized mammalian egg to cause one or more copies of the rDNA to be retained in the cells of the developing mammal. Usually up to 40 percent of the mammals developing from the injected eggε contain at leaεt 1 copy of the rDNA in their tiεεues. Theεe tranεgenic mammalε uεually transmit the gene through the germ line to the next generation. The progeny of the transgenically manipulated embryos may be tested for the presence of the construct by Southern blot analysis of a segment of tissue. Typically, a small part of the tail is used for this purpose. The stable integration of the rDNA into the genome of the transgenic embryoε allows permanent transgenic mammal lines carrying the rDNA to be established. Alternative methods for producing a non-human mammal containing a rDNA of the present invention include infection of fertilized eggs, embryo-derived stem cells, totipotent embryonal carcinoma (Ec) cells, or early cleavage embryos with viral expression vectors containing the rDNA. See for example, Palmiter et al, Ann. Rev. Genet.. 20:465-499 (1986) and Capecchi, Science. 244:1288-1292 (1989). A transgenic mammal can be any species of mammal, including agriculturally significant species, such as sheep, cow, lamb, horse and the like. Preferred are animals significant for scientific purposes, including but not limited to rabbits, primates and rodents, such as mice, rats and the like. A transgenic animal is not human. A transgenic animal is an animal that has been transformed by the introduction of a recombinant nucleic acid molecule into its genome. Typically, the recombinant nucleic acid molecule will be present in all of the germ cells and somatic cells of the transgenic animal. See for example, Gasser et al, Science. 244:1293-1299 (1989); European Patent Application No. 0257472 filed August 13, 1987 by De La Pena et al; PCT Pub. No. WO 88/02405 filed October 1, 1987 by Trulson et al; PCT Pub. No. WO 87/00551 filed July 16, 1986 by Verma, and PCT Pub. No. WO 88/09374 filed May 20, 1988 by Topfer et al. Methods for producing transgenic animals containing a rDNA of the present invention include standard transgenic technology; infection of the zygote or organism by viruses including retroviruseε; infection of a tiεsue with viruseε and then reintroducing the tiεεue into an animal; and introduction of a rDNA into an embryonic stem cell of a mammal followed by appropriate manipulation of the embryonic stem cell to produce a transgenic animal. See for example, Wagner et al, U.S. Patent No. 4,873,191 (Oct. 10, 1989); Rogers et al, Meth. in Enzvmol.. 153:253-277 (1987); Verma et al, PCT Publication No. WO87/00551; Cocking et al. Science. 236:1259-1262 (1987); and Luskin et al. Neuron 1:635- 647 (1988) . Transgenic animals having at least 1 cell containing the rDNA's of the present invention can be produced using methods well known in the art. See for example, Wagner et al, U.S. Patent No. 4,873,191 (Oct. 10, 1989) ; Hogan et al, Manipulating the Mouse Embryo: A Laboratory Manual, Cold Springs Harbor, New York (1987); Capecchi, Science. 244:288-292 (1989); and Luskin et al, Neuron 1:635-647 (1988) . 'In preferred embodiments a transgenic mammal of the present invention is produced by: 1) microinjecting a subject rDNA into a fertilized mammalian egg to produce a genetically altered mammalian egg; 2) implanting the genetically altered mammalian egg into a host female mammal; 3) maintaining the host female mammal for a time period equal to a εubεtantial portion of a gestation period of said mammal; 4) harvesting a tranεgenic mammal having at leaεt one cell containing a rDNA that has developed from the genetically altered mammalian egg. A fertilized mammalian egg may be obtained from a suitable female mammal by inducing superovulation with gonadotropins. Typically, pregnant mare's serum is used to mimic the follicle-stimulating hormone (FSH) in combination with human chorionic gonadotropin (hCG) to mimic luteinizing hormone (LH) . The efficient induction of superovulation in mice depends as is well known on several variables including the age and weight of the females, the dose and timing of the gonadotropin administration, and the particular strain of mice used. In addition, the number of superovulated eggs that become fertilized depends on the reproductive performance of the stud males. See, for example. Manipulating the Embryo: A Laboratory Manual. Hogan et al, eds.. Cold Spring Harbor, NY (1986) . The rDNA may be microinjected into the mammalian egg to produce a genetically altered mammalian egg uεing well known techniqueε. Typically, the rDNA is microinjected directly into the pronuclei of the fertilized mouse eggs as has been described by Gordon et al, Proc. Natl. Acad. Sci.. USA. 77:7380-7384 (1980) . This leads to the stable chromosomal integration of the rDNA in approximately 10 to 40 percent of the εurviving embryoε. See for example, Brinεter et al, Proc. Natl. Acad. Sci.. USA, 82:4438- 4442 (1985) . In moεt cases, the integration appears to occur at the 1 cell stage, as a result the rDNA is present in every cell of the tranεgenic animal, including all of the primordial germ cells. The number of copies of the foreign rDNA that are retained in each cell can range from 1 to several hundred and does not appear to depend on the number of rDNA injected into the egg as is well known. An alternative method for introducing genes into the animal'ε germ line iε the infection of e bryoε with viruε vectorε. The embryos can be infected by either wild-type or recombinant viruses leading to the stable of integration of viral genomes into the host chromoεomeε. See, for example, Jaenisch et al, Cell. 24:519-529 (1981). One particularly useful class of viral vectors are virus vector derived from retro- viruses. Retroviral integration occurs through a precise mechanism, leading to the insertion of single copies of the virus on the host chromosome. The frequency of obtaining transgenic animals by retroviral infection of embryos can be as high as that obtained by microinjection of the rDNA and appears to depend greatly on the titer of virus used. See, for example, van der Putten et al, Proc. Natl. Acad. Sci., USA. 82:6148-6152 (1985). Another method of transferring new genetic information into an animal embryo involves the introduction of the rDNA into embryonic stem cells and then introducing the embryonic stem cellε into the embryo. The embryonic εtem cells can be derived from normal blaεtocyεtε and theεe cellε have been shown to colonize the germ line regularly and the somatic tisεues when introduced into the embryo. See, for example, Bradley et al, Nature, 309:255-256 (1984) . Typically, the embryo-derived stem cells are transfected with the rDNA and the embryo-derived εtem cellε further cultured for a time period sufficient to allow the rDNA to integrate into the genome of the cell. In some situations this integration may occur by homologouε recombination with a gene that iε present in the genome of the embryo-derived stem cell. See, for example, Capecchi, Science, 244:1288-1292 (1989) . The embryo stem cells that have incorporated the rDNA into their genome may be selected and used to produce a purified genetically altered embryo derived stem cell population. See, for example, Mansour et al, Nature. 336:348 (1988). The embryo derived stem cell is then injected into the blastocoel cavity of a preimplantation mouse embryo and the blastocyst is surgically transferred to the uterus of a foster mother where development is allowed to progresε to term. The resulting animal is chimeric in that it is composed from cells derived of both the donor embryo derived stem cells and the host blastocyst. Heterozygous siblings are interbred to produce animals that are homozygous for the rDNA. See for example, Capecchi, Science. 244:1288-1292 (1989). The genetically altered mammalian egg is implanted into host female mammals. Methods for implanting genetically altered mammalian eggs into host females are well known. See, for example, Hogan et al, Manipulating the Mouse Embryo: A Laboratory Manual. Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (1986) . Pseudopregnant recipient femaleε may be produced by mating females in natural estruε with vaεectomized or genetically sterile males. After mating with a sterile male, the female reproduction tract becomes receptive for transferred embryos even though her own unfertilized eggs degenerate. The genetically altered mammalian eggs are then transferred to the ampullae or the uterine horns of the pseudopregnant recipient. If the genetically altered mammalian egg is transferred into the ampullae it must be enclosed in a zona pellucida membrane. If it is transferred into the uterine horns the genetically altered mammalian egg does not require a zona pellucida membrane. The host female mammals containing the implanted genetically altered mammalian eggs are maintained for a sufficient time period to give birth to a transgenic mammal having at least 1 cell containing a rDNA of the present invention that has developed from the genetically altered mammalian egg. Typically thiε gestation period is between 19 to 20 days depending on the particular mouse strain. The breeding and care of mice is well known. See for example, Manipulating the Mouse Embryo: A Laboratory Manual. Hogan et al, eds., Cold Spring Harbor, New York, (1986) . The infection of cells within an animal using a replication incompetent retroviral vector has been deεcribed by Luskin et al, Neuron, 1:635-647 (1988). Examples The following exampleε relating to thiε invention are illuεtrative and εhould not, of course, be construed as specifically limiting the invention. Moreover, such variations of the invention, now known or later developed, which would be within the purview of one skilled in the art are to be considered to fall within the scope of the preεent invention hereinafter claimed. 1. Preparation of MR22 and REC17 Iεolated Serotonin Receptors Molecular cloning has indicated that serotonin (5-hydroxytryptamine, also referred to as 5-HT) receptors belong to at least two protein superfamilies: G-protein-associated receptors which have seven putative transmembrane domains (TMDs) (5-HTi AB/ c /D/E , 5-HT 2 and rat stomach fundus) and ligand-gated ion channel receptorε which have four putative TMDε (5-HT ) . Presently, ten distinct mammalian genes encoding G-protein-coupled serotonin receptors have been cloned: five coupled to the inhibition of adenylate cyclase { - as described by Albert et al., J. Biol. Chem.. 265:5825-5832 (1990), Voigt et al., EMBO J.. 10:4017-4023 (1991), Zgombick et al., Mol. Pharmacol.. 40:1036-1042 (1991), McAllister et al., Proc. Natl. Acad. Sci.. USA. 89:5517-5521 (1992), and Amlaiky et al., J. Biol. Chem.. 267:19761-19764 (1992), three coupled to phosphotidylinositol-4,5-bisphoεphate hydrolysis (5-HT lc 22F ) as described by Julius et al.. Science. 241:558-564 (1988), Pritchett et al., EMBO Jj_, 7:4135-4140 (1988), and Foguet et al. , EMBO J.. 11:3481-3487 (1992), and two of unknown coupling (5-HT 5Af5B ) as described Plassat et al., EMBO J.. 11:4779-4786 (1992). In addition, the 5-HT 3 receptor gene has been cloned, but this receptor belongs to the family of ligand-gated ion channels. Novel G-protein-associated receptors were identified in a polymerase chain reaction (PCR) using degenerate primers corresponding to strongly conserved εequenceε within their TMDs as described by Libert et al., Science. 244:569-572 (1989), the discloεure of which iε hereby incorporated by reference. Thiε strategy has been refined in thiε invention εo aε to target novel εerotonin-like receptorε εpecifically. The iεolation of novel receptorε that only bound indoleamine was accomplished by the methods of this invention where two sequential rounds of nested PCR were performed on a rat brain hypothalamic cDNA template. In the second round of PCR, degenerate primers corresponding to conserved residueε εpecific to indoleamine-binding receptorε were used to amplify only those receptors. The resulting products were then cloned into pKS pBluescript vectors. Resultant colonies were screened and plasmids from selected colonies were then sequenced. The plasmid fragments were then used to probe a rat hypothalamus cDNA library to obtain full length clones encoding the isolated receptors described in Example 1. The cloning and identification of a novel subfamily of 5-HT receptors of this invention whose members belong to the G-protein-associated superfamily is more fully described below. A. PCR Amplification Serotonin receptors were examined as a group to determine whether they contained amino acid sequenceε that diεtinguished them from other G protein-coupled receptors. Sequenceε in TMD V received extra scrutiny because previous site-directed mutagenesiε experimentε of catecholamine receptorε had de onεtrated that thiε region iε required for binding the catechol ring structure. See, Strader et al., FASEB J.. 3:1825-1832 (1989). The sequenceε required to bind indolamine ring εtructureε were εur iεed to replace catechol-binding εequenceε in TMD V and that differenceε between indoleamine and catecholamine-binding εequences could be exploited experimentally to isolate indoleamine binders specifically. In the εequences of all known 5-HT receptors available (δHT^, 5-HT lc and 5-HT 2 ) , a consensus in TMD V existed that differed in 2 positions from catechol-binding receptors. To test this hypothesis, cDNA was produced from rat hypothalamic mRNA as described below and amplified in two sequential rounds of PCR. The primerε in the firεt PCR round were degenerate, encoding all possible codons of Cys-Ala-Ile-Xaa-Leu-Asp-Arg-Tyr (SEQ ID NO 12) where Xaa iε either Ala or Ser in TMD III and the complement of Xaa α -Trp-Xaa 2 -Pro-Phe-Phe-Ile (SEQ ID NO 13) where Xaa x was either Cys or Met and Xaa 2 was either Leu or Cys in TMD VI. This first round was expected to amplify sequences corresponding to most known catechol and all known serotonin (5-HT) receptors. Amplified PCR products from this reaction were used as the substrate for a second round of PCR with the same 5• primer and a different 3 • primer for TMD V, the latter of which was a degenerate complement of all possible codons of Phe-Xaai-Ala-Phe-Xaaji-Ile-Pro-Leu, (SEQ ID NO 14) where Xaa x was either Val or Gly and Xaa 2 was either Phe or Tyr. This primer pair was expected to amplify sequences corresponding to 5-HT 1A , 5-HT 1c , and 5-HT 2 receptors, and possibly those of novel 5-HT receptors. For preparing the hypothalamic cDNA, polyadenylated (poly(A) + ) RNA waε isolated from dissected rat hypothalami using Micro Faεt Track kitε (Invitrogen, San Diego, CA) and uεed as a template for first strand syntheεiε of cDNA by Maloney murine leukemia viruε (MMLV)-Reverεe Tranεcriptaεe (Stratagene, La Jolla, CA) . The resulting cDNAs were then εubjected to amplification by PCR with the uεe of a set of highly degenerate oligonucleotide primers. The first round of PCR on the rat hypothalamus cDNA prepared above was performed using degenerate primers corresponding to conserved regions in TMDs III and VI of both catecholamine and serotonin receptors. Nucleotide sequences of the pool of the 5' end TMD III degenerate oligonucleotide primerε used in the first round were 5'-AGCTCCGCGGAGCTCTATGYGCNATHGCNYTNGAYMGNTA-3 ' (SEQ ID NO 15) and 5'-AGCTCCGCGGAGCTCTATGYGCNATH SNYTNGAYMGNTA-3 ' (SEQ ID NO 16) , where N was either A, C, G or T; Y was either T or C; H was either T, C or A; M was either A or C; was either A or T; and S was either C or G. The restriction sites, SacI-SstI, designed into the III degenerate oligonucleotides in tandem for facilitating cloning into pKS pBluescript, are indicated by the underlined nucleotides. Nucleotide sequences of the pool of the 3 ' end TMD VI degenerate oligonucleotide primers used in the first round were 5 ■ -AGCTCCGCGGAGCTCDATRAARAANGGNARCCARCA-3' (SEQ ID NO 17) and 5'-AGCTCCGCGGAGCTCDATRAARAANGGRCACCACAT-3' (SEQ ID NO 18). where N was either A, C, G or T;.D was either G, A or T; and R was either A or G. The restriction siteε, SacI-SstI, designed into the VI degenerate oligonucleotides in tandem for facilitating cloning into pKS pBluescript, are indicated by the underlined nucleotides. The first PCR amplification was performed for 30 cycles where each cycle consisted of 95 degrees Celsius (94°C) for 1 minute, 45°C for 1 minute, and 72°C for 3 minutes with a Perkin Elmer Cetus 9600 thermal cycler (Perkin Elmer Cetuε, Norwalk, CT) . The reaction mixture waε prepared by admixing 10 microliterε (μl) of 10X PCR buffer (Perkin Elmer Cetuε) , 5 μl dimethylεulfoxide, 4 μl of 25 millimolar (mM) deoxynucleotides (dNTP's) , 7.5 micrograms (μg) each of the 5 • and 3 ' pools of oligonucleotide primers, 2.5 u/μl Taq polymerase (Perkin Elmer Cetuε) , 2 μl MgCl 2 and water for a final volume of 100 μl. The resultant products that exceeded 500 bases were then isolated by agarose gel electrophoresiε and used as templateε for a second PCR amplification with oligonucleotide primer pools III and V. The 3' end oligonucleotide degenerate primer V corresponded to a conserved region of TMD V, the amino acid residue sequence of which is shown above, specific only for serotonin receptors. The nucleotide sequence of the pool of the V degenerate oligonucleotide primers used in the second round was 5 •-ACGTGCGGCCGCNARNGGDATR ARAANGCNMCRAA-3 • (SEQ ID NO 19) where N was either A, C, G or T;.D was either G, A or T; R was either A or G; was either A or T; and M was either A or C. Adapter sequences on the 5' ends of the primers were designed into the oligonucleotide primers to provide for directional ligation of the resultant doubly-amplified cDNAs into recipient pKs pBluescript vectors. The restriction sites SacI-SstI were built into the oligonucleotide III. The restriction site, NotI, was built into the oligonucleotide V. Thus, the doubly-amplified PCR fragments had SacI-SstI and NotI restriction sites respectively at the 5* and 3 1 ends of the fragmentε. B. Cloning and Sequence Analvεis The products resulting from the PCR amplifications performed in Example 1A were then digested with Sad and NotI for ligation into SacI-NotI linearized plaεmid pKε pBluescript vector (Stratagene) . The resultant vectors containing the amplified sequences were then used to transform competent DH5 bacteria (BRL, Bethesda, MD) by the calcium chloride method. A pool of radiolabeled oligonucleotides at 100 nanograms (ng) each diluted in approximately 5 milliliterε (ml) of hybridization buffer correεponding to a non-conεerved portion of the third intracellular loop for the rat 5-HT 1A (ntε 1002-976) (S'-TCGGACCCCGACGCGTGCACCATC-S' SEQ ID NO 20) , 5-HT 1c (nts 879-856) (5»-GTGAATAACACCACGTGCGTGCTC-3' SEQ ID NO 21) , and 5-HT 2 (ntε 1515-1488) (5 1 -AAGGAGGGGAGCTGCCTGCTTGCC-3 ' SEQ ID NO 22) receptorε to screen approximately 1000 transformed DH5 bacterial colonies. By using the specified pool of oligonucleotide probes for screening the transmembrane domain-specific amplified transformed cells, clones corresponding to these known receptors were successfully eliminated from further consideration. In this negative εelection screening protocol, only the clones that failed to hybridize to the pool of nucleotide probed were selected for further cloning, sequencing and characterization. Two clones, MR22 and MR77, failed to hybridize and were shown to have sequenceε distinct from one another. All sequencing was performed according to the dideoxy-termination method described by Sanger et al., Proc. Natl. Acad. Sci.. USA. 74:5463-5467 (1977) and analyzed using Genetics Computer Group sequence software (Madison, I) aε deεcribed by Devereux et al., Nuc. Acidε Reε.. 12:387-395 (1984) . The MR22 PCR cDNA clone selected from the screening procedure above was then used to probe an amplified rat hypothalamic cDNA library (4 X 10 6 recombinants in unamplified library) conεtructed in lambda ZAPII. Of the cloneε obtained from εcreening the hypothalamic library, two clones hybridized strongly and six clones hybridized weakly. The two strongly hybridizing clones had identical inserts of 1905 base pairs (bp) , containing an exact match to the original MR22 sequence; thus, the MR22 nomenclature was maintained to identify this clone. The six weakly hybridizing clones had identical inserts of 1511 bp. Because the nucleotide sequence was only 65% identical to that of MR22 and thus distinct, this clone was designated REC17. Anchored PCR (APCR) was performed with dG-tailed hypothalamic cDNAs used as a template in order to obtain full length clones encoding MR22 and REC17. Anchored PCR was performed by first converting poly(A) * -selected RNA extracted from rat brain to first strand cDNA using random hexamer oligonucleotide primers and MMLV-reverse transcriptase. The cDNAs were subsequently tailed with dGTP using terminal transferase. Anchored PCR was performed as described by Frohman et al., Proc. Natl. Acad. Sci.. USA. 85:8998-9002 (1988) using this dG-tailed cDNA as a template. For MR22 APCR, a primer complementary to nucleotides 385 to 404 (5'-GGATCCCATGCTTCTGCCGG-3 •) (SEQ ID NO 23) of the determined MR22 sequence and an anchored primer (5•-GCACCGCGGAGCTCAAGCTTCCCCCCCCCCCCCCCCCCCCC-3• ) (SEQ ID NO 24) were used. ACPR was performed as described for PCR above with the exception of the primers listed above and the 10X APCR buffer, the latter of which was prepared by admixing 16.7 ml of l M (NH 2 S0 4 , 67 ml of 1 M Tris-HCl at pH 8.8, 5 ml of 2% gelatin, 6.7 ml 1 M MgCl 2 and 4.6 ml water for a total volume of 100 ml. Ten percent of the reεulting productε were εeparated by gel electrophoresis and transferred onto nitrocellulose. The nitrocellulose filter was then hybridized with a radioactively labeled oligonucleotide representing nucleotides 320 to 340 of the MR22 sequence listed in SEQ ID NO 1. A major band of approximately 400 bp was detected. The remaining product was digeεted with Hindlll, separated by electrophoresiε, and the 400 bp fragment excised and subcloned into the Hindlll site of pKS pBluescript for nucleotide sequence determination. An additional 319 base pairs (bp) of the 5' end of the clone was isolated using this procedure. In composite, the MR22 cDNA (SEQ ID NO 1) is 2226 bp in length and contains an open reading frame (ORF) encoding 370 amino acids beginning 303 nucleotides from the 5' end as shown in Figure 1. The derived amino acid residue sequence of the MR22 cDNA clone, also shown in Figure 1, is listed as SEQ ID NO 2. For the REC17 APCR, a primer complementary to nucleotides 626 to 650 of REC17 was used (5'-TGCCCAAGTGAGCAGGATCATCACG-3') (SEQ ID NO 25) and the radiolabeled REC17-specific probe was complementary to nucleotides 562 to 586 (5'-TGGCGCGTTATTGACCAGTAGCGGT-3') (SEQ ID NO 26) . A major band of approximately 700 bp hybridized to the labeled probe and was excised, subcloned, and sequenced as described for MR22. Anchored PCR provided an additional 644 bp of sequence. In composite, the REC17 cDNA in SEQ ID NO 3 contains an ORF encoding 357 amino acids as shown in Figure 2. The amino acid sequences of the putative MR22 (SEQ ID NO 2) and REC17 (SEQ ID NO 4) proteins are 68% identical and can be optimally aligned with 3 gaps. Thus, by performing the amplification strategieε, PCR-derived cDNAs were obtained and used to probe a rat hypothalamus cDNA library (MR22 or REC17) to obtain MR22 and REC17-specific clones spanning the entire coding regions as described above. Based on the determined nucleotide sequence, they were found to putatively encode a protein with the amino acid residue sequence characteristic of the G-protein-coupled, seven-TMD receptor superfamily. Confirmation of the identity and relationship of MR22 and REC17 receptors to known serotonin receptors was accomplished by nucleotide sequence comparison analysis, mRNA distribution and abundance mapping, and protein functional characterization as described in Example 4. C. Expression In order to produce recombinant MR22 and REC17 receptor proteins for use in this invention, the MR22 and REC17 cDNAs prepared above were subcloned into the eucaryotic expression vector, pCMV4. The pCMV4 expression vector, obtained from Dr. David Russel, Department of Molecular Genetics, University of Texas, Southwestern Medical Center, Dallas, Texas, was prepared as described by Russel et al., J. Biol. Chem.. 264:8222-8229 (1989), the disclosure of which is hereby incorporated by reference. An alternative expression vector for uεe in expreεsing the serotonin receptors of thiε invention iε pRc/CMV commercially available from Invitrogen, San Diego, CA with the catalog number V750-20. The pRc/CMV expression vector contains enhancer and promoter sequenceε from the immediate early gene of human cytomegalovirus (CMV) for high level tranεcription. The vector alεo containε the a picillin reεiεtance gene and ColEl origin for selection and maintenance in E. coli. For subcloning MR22 cDNA into pCMV4, the joining of the two overlapping cDNAs of MR22, which in composite contained the entire coding region, was required prior to subcloning into pCMV4. By using an unique but overlapping restriction site PflMI, these two cDNAs were joined together and εubcloned into pKs pBluescript. To subclone into the pCMV4 expression vector, MR22 in pBluescript and pCMV4 were then double digested in parallel with Kpnl and Xbal and then the MR22 cDNA containing the entire coding region was directionally ligated into the linearized pCMV4 expression vector to form pCMV4MR22. For subcloning REC17 into pCMV4, aε with MR22, the joining of the two cDNAs representing as a whole the entire coding region of REC17 was required prior to subcloning into pCMV4. This was accomplished with the same procedure as described for MR22. The REC17 complete cDNA in pBluescript was then digested with Kpnl and Hindlll and directionally ligated into a similarly digested pCMV4 expression vector to form pCMVREC17. CosM6 cells, a subclonal line of COS-7 cells (American Type Culture Collection (ATCC) accession number 1651, ATCC, Rockville, MD) , or HeLa cells (ATCC accession number CCL2) were then separately transfected with pCMV4MR22 (MR22 cDNA) and pCMV4REC17 (REC17 cDNA) prepared above. Also tranεfected into the hoεt cellε were the following control expreεεion vectorε: l) pDPSHTla, for expreεsing a known εerotonin receptor of εubclaεε 5-HT la as described by Kobilka et al., Nature. 329:75-79 (1987) and 2) pBC12BIBeta2 for expreεsing a known hamster beta2-adrenergic receptor as deεcribed by Kobilka et al., Proc. Natl. Acad. Sci.. USA. 84:46-50 (1987) . The latter gene waε cloned into the pBC12BI eucaryotic expresεion vector (ATCC acceεsion number 67617) . The transfections into the CosM6 cells and HeLa cells were respectively performed by the DEAE dextran and calcium phosphate methods with 10 μg of a selected cesium chloride-purified plasmid per 10 centimeter dish. Alternative cell lines for either transient or stable expression of recombinant serotonin receptor proteins of this invention include NIH3T3 (ATCC accession number CRL1658) (stable) , COS-7 (transient) , HEK293 (ATCC accession number CRL1573) (stable, Ltk (stable) , AV-12 (ATCC accession number CRL9595) (stable) , COS-1 (transient) , and the like. Approximately 60 hours after transfection, CosM6 cells were removed from dishes using Versene (Gibco, Gaithersburg, MD) and a cell scraper, then collected by centrifugation (1,000 rpm for 5 minutes) . Pellets were resuspended in 50 mM Tris-HCl, pH 7.6 with a polytron homogenizer, centrifuged (40,000 x g for 20 minutes) and resuspended in the same buffer (500 μl/10 cm dish) . Once expressed and purified, the recombinant serotonin receptor proteins, MR22 and REC17 , were then used in binding asεayε aε described in Example 4D. 2. Preparation of MR77 Isolated Serotonin Receptors A. PCR Amplification Highly degenerate oligonucleotides were designed corresponding to conserved amino acid sequences in putative transmembrane domains III, V, and VI of the 5-HT 1A , 5-HT 1c , and 5-HT 2 receptor. These oligonucleotides were used in sequential polymerase chain reactionε (PCR) aε described in Example 1A with rat hypothalamus cDNA as the template to generate a series of cloneε. Complementary DNA was prepared from poly (A) + -enriched RNA as described in Example 1A. Oligonucleotideε of degenerate εequence were εyntheεized corresponding to conserved amino acid sequences of portionε of putative transmembrane domains III, V, and VI of the 5-HT 1A and 5-HT 1c receptors as shown in Example 1A. The two roundε of PCR were performed aε described in Example 1A with the same pairs of oligonucleotide primers used in each reaction. The resultant PCR amplification products were then cloned into pBluescript vectors as described below. B. Cloning and Seguence Analysis The resulting amplification products prepared in Example 2A were then ligated into pKs pBlueεcript (Stratagene) and used to transform DH5 bacteria (BRL) as described in Example 1A. Bacterial transformation resulted in approximately 1000 colonies, of which more than 95% hybridized to a mixture of radiolabeled oligonucleotides corresponding to non-conserved regions located between transmembrane domains III and V of the rat 5-HT 1A (nts 1002-976) (S'-TCGGACCCCGACGCGTGCACCATC-S' SEQ ID NO 20), 5-HT 1c (nts 879-856) (5'-GTGAATAACACCACGTGCGTGCTC-3' SEQ ID NO 21) , and 5-HT 2 (nts 1515-1488) (5'-AAGGAGGGGAGCTGCCTGCTTGCC-3' SEQ ID NO 22) receptors. Thirty six colonies which showed either minimal or no hybridization were picked, reprobed with the same oligonucleotide mixture, and partial sequences of non-hybridizing clones were determined. From this εcreening, two distinct cDNA clones were iεolated whoεe sequences had significant similarity to G-protein-asεociated receptorε. One of the cDNA clones, designated MR77, is a novel εerotonin receptor-encoding cDNA of thiε invention. A rat hypothalamuε cDNA library waε εcreened aε deεcribed in Example IB with the MR77 cDNA. No cloneε were obtained in this screen. Since many neurotransmitter receptor genes of this superfamily do not contain introns, it waε hypotheεized that a genomic clone may contain an intact open reading frame. Thuε, a rat genomic library (Stratagene) waε probed with radiolabeled MR77 DNA prepared as described for MR22 and REC17 DNA in Example 2B. This εcreen resulted in the isolation and subsequent subcloning of a 2.5 kb fragment which contained an apparently intronless open reading frame of 1098 nucleotides. However, the reading frame upstream from an apparent initiation codon was also open. Anchor-PCR protocol was then performed as described in Example IB with an oligonucleotide primer complementary to nucleotides 311 to 289 (δ'-GGCTGGGTGGTGCAGCTTCCG-S 1 ) (SEQ ID NO 27) of the determined MR22 sequence and an anchored primer (5•-GCACCGCGGAGCTCAAGCTTCCCCCCCCCCCCCCCCCCCCC-3•) (SEQ ID NO 24) were used. The template used was dG-tailed rat brain cDNA. The largest product was cloned. All sequencing was performed according to the dideoxy-ter ination method as described in Example 1A using Sequenase (United Stateε Biochemical) . Sequence data were compiled and analyzed uεing Geneticε Computer Group εequence εoftware (Madiεon, I) . The sequence of thiε partial MR77 cDNA clone εhown in Figure 3 (SEQ ID NO 5) waε identical to the genomic clone from nucleotide 97 to 311, but waε completely different at itε 5' end beginning 41 nucleotideε upεtream from the preεumed initiation codon. The rat MR77 cDNA sequence contained stop codons in frame with the putative coding sequence suggesting that the assignment of the initiation codon was correct. Upon closer examination of the genomic clone, an intron acceptor site was detected at nucleotide 97 as shown in Figure 3 denoted by the asterisk (*) . The sequence shown in Figure 3 in bold print and listed in SEQ ID NO 6 represents the MR77 cDNA sequence which is different from the genomic clone. The intron lies upstream from the complete open reading frame encoding the putative receptor. Because the open reading frame encoded a 366 amino acid sequence shown in Figure 3 and SEQ ID NO 7 that is highly related to known receptors throughout its entire length, the mRNA was determined to not contain additional intronε. Human homologs of all of the receptor genes of this invention can be obtained by low stringency hybridization of the rat receptor probes to cDNA or genomic libraries constructed from human tissue. Many libraries are commercially available from companies such as.Stratagene, La Jolla, CA and Clontech, Palo Alto, CA. The MR77 cDNA was used to probe a commercially available human genomic library (Stratagene, catalog #943202) . The human library was screened following the same procedure deεcribed herein for εcreening the rat hypothalamuε cDNA library. The εequence of the human MR77 homolog waε determined which iε 86% and 93% identical to rat MR77 at the nucleic acid and amino acid εequence levelε, respectively. The human amino acids that differ from those of rat are shown in italicε in Figure 3. The nucleotide and amino acid reεidue sequences of the human MR77 are respectively listed in SEQ ID NO 8 and 9. The nucleotide sequences of the rat and human clones can be acceεsed from GenBank, accesεion numbers are L05596 and L05597, respectively. Further characterization of the novel MR77 serotonin receptor was determined by comparison of the nucleic and derived protein sequence of MR77 with known serotonin receptors is described in Example 4A. The tissue distribution of the mRNA as described in Example 4B and the comparison with other known serotonin receptors along with the new receptors of this invention are described in Example 4E. c ' Expresεion The original subclone of MR77 prepared in Example 2A contained several ATGs in the DNA sequence upstream of the translational start codon. Therefore, to guarantee correct expression of the MR77 protein in eucaryotic cells, the MR77 cDNA subclone contained within the pCMV4 vector needed to be devoid of these upstream DNA sequences. The overall strategy for subcloning was as follows: PCR amplification of the DNA encoding the N-terminal portion of MR77 (from the start codon, ATG to a unique SphI site) was completed using the original MR77 DNA as template. For the amplification via PCR the 5• primer containing the ATG sequence and flanking NotI and Hindlll sites was 5'-CAGCTACGGCGGCCGCAAGCTTAAAATGGATTTTCTAAACTCA-3 ' (SEQ ID NO 28) and the 3' primer containing the internal unique SphI site was 5'-CTGTTGTAATCGTGATGCCAGCATGC-3 ' (SEQ ID NO 29). The resulting PCR products were then double digested in parallel with the original MR77 clone which was cloned in pBluescript aε deεcribed in Example IB. The digested PCR products were subcloned into the digested and linearized MR77-containing pBlueεcript vector, thuε replacing the original MR77 5• end and εubεequently the upεtream and undeεirable ATGε. Thiε new MR77 εubclone waε then double digeεted with Hindlll and Smal and directionally ligated into a εimilarly digeεted pCMV4 expreεεion vector prepared aε described in Example IB. The resultant expression vector, designated pCMV4MR77, contained the entire coding region of MR77. The recombinant MR77 serotonin receptor protein was expressed as described for MR22 and REC17 proteins in Example IC. The MR77 protein was then used in binding assays as described in Example 4D to confirm the specificity of the novel receptor. 3. Preparation of REC20 Isolated Serotonin Receptors In order to gain an understanding of the role of serotonin in circadian rhythms and hypothalamic function, a paradigm targeted for discovering new serotonin and indoleamine receptorε, such as melatonin which is also thought to modulate endogenous clock function, waε deεigned. In an attempt to identify more receptorε which belong to the recently characterized family of 5-HT 5 receptorε, a PCR strategy similar to those previously deεcribed in Exampleε 1 and 2 waε deεigned aε deεcribed below. A. PCR Amplification For iεolating the novel REC20 εerotonin receptor of thiε invention, a different amplification procedure waε deεigned than that uεed to amplify MR22, REC17 and MR77 aε deεcribed in Exampleε 1 and 2. Aε will be described herein, degenerate primers corresponding to regions of TMD III and TMD VII that are conserved among catecholamine and serotonin receptors, were used in the first round of PCR. Then, the εecond round of PCR waε performed using a degenerate primer corresponding to residue in TMD V specific to MR22 and REC17 in conjunction with the previously used TMD VII primer. The two step PCR amplification procedure was performed as described in Example 1A with a few modifications. Oligonucleotides of degenerate sequence where synthesized corresponding to conserved transmembrane domains (TMD) III and VII of known serotonin receptors. The amino acid sequence of domain III along with the nucleotide sequence of the degenerate oligonucleotide primer pool for amplifying this region is described in Example 1A. The amino acid sequence of the TMD VII is Trp-Xaai-Gly-Tyr-Xaaz-Asn-Ser-Xaas (SEQ ID NO 30) where Xaaj was either Leu or lie, Xaa 2 was either Leu or Ser and Xaa 3 was either Leu or Phe. The degenerate 3' oligonucleotide primer pool for amplifying the TMD VII region has the nucleotide sequence 5'-GCTCATCTAGANARNSWRTTNVDRTANCCNADCCA-3' (SEQ ID NO 31), where N was either A, C, G or T, R was either A or G, S was either G or C, W was either A or T, V waε either A, G or C, and D waε either A, G or T. The underlined nucleotides indicate an Xbal restriction εite to facilitate the directional cloning of the amplified productε. Theεe oligonucleotideε were uεed to amplify rat brain cDNA as described in Example 1A. The template included cDNA from whole brain, hypothalamus, hippocampus, and cerebral cortex. The products of this reaction were then used as template in a second reaction with the same TM VII oligonucleotide shown above, but with the 5' degenerate oligonucleotide primer pool corresponding to a region downstream of TMD V, conserved only between the 5-HT 5A and 5-HT 5B receptorε having the amino acid reεidue sequence Phe-Val-Tyr-Trp-Lys-Ile-Tyr-Lyε (SEQ ID NO 32) . The V degenerate oligonucleotide pool waε derived from the nucleotide sequence 5•-CTGGTGGTCGACGGTACCTTYGTNTAYTGGAARATHAYAA-3 ' , (SEQ ID NO 33) where N was either A, C, G or T, Y was either T or C, R was either A or G and H was either T, C or A. The TMD V degenerate oligonucleotide contained tandemly arranged restriction endonuclease sites, Sall-Kpnl, at the 5' end of the primer as indicated by the underlined nucleotides. The second set of primers were highly degenerate in sequence, but corresponded to regions conserved only in the identified 5-HT 5A and 5-HT 5B receptor genes described in Example 1, reεpectively REC17 and MR22. The εecond round of PCR amplification with the V and VII oligonucleotide primer poolε with the first PCR amplification products as a template was performed as described in Example 1A. The resultant PCR amplification productε contained the reεtriction εiteε, Sall-Kpnl and Xbal, reεpectively at the 5 1 and 3' endε to allow for directional ligation into pBlueεcript aε deεcribed in Example 3B. B. Cloning and Seguence Analvεiε The productε of the εecond PCR amplification prepared above were εubcloned into pBluescript (Stratagene) and used to transform DH5 cells (BRL) as described in Example IB. The resultant colonies were probed with a mixture a radiolabeled oligonucleotides that were 20 nucleotideε in length specific to 5-HT 5A and 5-HT 5B receptorε. The probeε used in the screening had the following nucleotide sequences: 5'-CCTCAGGAGTCTGAGACGGTATTC-3 • (SEQ ID NO 34) and S'-GCTGTGGAGGTGAAGGACGTTCAC-S' (SEQ ID NO 35). Negative selection was performed as described in Example IB. The two colonies which did not hybridize were picked, grown, and the sequence of the plasmid inserts determined. One of these fragments, number 20, was radiolabeled and used to then screen a rat hypothalamus cDNA library also as described in Example IB. Positive clones were purified, digested with EcoRI, subcloned, and their sequence determined according to the dideoxy-termination method as described in Example IB using Sequenase (USB, Cleveland, OH) . Thus, this PCR amplification strategy and screening resulted in the selection of a novel serotonin receptor designated REC20. The nucleotide and derived amino acid sequence of REC20, shown in Figure 5, are listed respectively in SEQ ID NO 10 and 11. The 5-HT 6 receptor cDNA, isolated from a rat hypothalamus library, encodes a putative protein of 435 amino acids and haε εeven predicted tranεmembrane domainε. Primary sequence analysis indicates that 5-HT 6 representε a new claεε of 5-HT receptorε within the G-protein coupled family. Additional characterization of the REC20 baεed on nucleotide εequence and amino acid εequence iε alεo deεcribed in Exampleε 4A and 4E. The recombinant REC20 receptor protein waε expreεεed aε deεcribed below. The human homologε of REC20 waε alεo iεolated from screening a human genomic library obtained from Stratagene with the REC20 cDNA clone as a probe as described in Example 2B for MR77. C. Expresεion The initial clone of REC20 waε 3.6 kb. A 2 kb fragment of the 3.6 kb clone was subcloned into the EcoRI site of pBluescript (Stratagene) . A fragment containing most of the coding sequence (minus the first 122 nucleotides of the coding sequence) with digested with Sad, blunt-ended this fragment, and ligated into pCMV4, prepared in Example IC, which had been predigested with Smal and treated with phoεphatase. The resultant plasmid vector containing the insert was designated pCMV4-20. A new fragment containing the first 122 nucleotides, starting with the initiator, ATG, was PCR amplified using an oligonucleotide containing the ATG (preceded by a restriction endonucleaεe εite for Hindlll) and an oligonucleotide correεponding to the reverse complement of nucleotides 1568-1592 of the original 2 kb clone. This fragment was digeεted with Hindlll and Nhel and ligated into pCMV4-20 which had been εimilarly digeεted. The resulting clone was sequence-confirmed. All sequencing was performed according to the dideoxy-termination method as described in Example 1A using Sequenase (United States Biochemical) . Sequence data were compiled and analyzed using Genetics Computer Group εequence εoftware (Madiεon, WI) . The REC20 recombinant protein waε then uεed for binding aεεayε aε deεcribed in Example 4D. 4. Characterization of Expressed Novel Serotonin Receptors A. Nucleotide and Protein Sequence Comparison 1) MR22 and REC17 Both MR22 and REC17 contain seven putative membrane spanning regions, and putative N-glycoεylation and phoεphorylation εiteε in poεitionε similar to known receptors as shown in Figures 1 and 2, consistent with the hypothesis that these two proteins belong to the G-protein-associated receptor superfamily. A search of the protein and nucleic acid databases with the entire MR22 putative protein sequence revealed the greatest amino acid sequence identities in the 30-35% range to alpha- and beta-adrenergic and 5-HT receptors from various species. REC17 yielded very similar results. Comparison of only the putative TMD regions of MR22 and REC17 with TMDs of other known G-protein-associated receptors gave qualitatively similar results, although the identities were in the 40-48% range, with none exhibiting dominant similarity. Thus, MR22 and REC17 are probable G-protein-associated receptors much more related to one another than to known receptors for various ligands. Consequently, sequence analysis did not provide the identity of the endogenous ligandε interacting with MR22 and REC17. 2) MR77 The MR77 protein sequence predicted from the cDNA clone contains seven hydrophobic regions as determined by hydropathy calculations performed as described by Kyte et al, ^ _ Mol. Biol.. 157:105-132 (1982). In addition, the N-terminal putative extracellular domain has two potential sites for asparagine-linked glycoεylation at amino acids five and ten as shown by the arrows in Figure 3. There are several potential protein kinase C (circleε) and calmodulin kinaεe II phoεphorylation (squares) sites in the large intracellular loop between putative transmembrane domains V and VI as εhown in Figure 3. Theεe potential poεt-tranεlational modificationε are similar to those predicted for a variety of G-protein-coupled receptors. See, Savarese et al., Biochem. J.. 283:1-19 (1992) and Rands et al., J. Biol. Chem.. 265:10759-10764 (1990). MR77 exhibits considerable amino acid homology, particularly within the transmembrane domains, with known 5-HT receptors that are coupled to the inhibition of adenylate cyclase: human S31 (5-HT 1E ) , dog 5-HT 1D , rat 5-HT 1B , rat 5-HT 1A , and rat 5-HT with 55%, 48%, 46%, 35%, and 30% overall identity. The primary amino acid sequence of MR77 is moεt cloεely related to the recently described human S31 receptor described by Levy et al., FEBS Lett.. 296:201-206 (1992) which has been identified as the 5-HT 1E receptor as described by McAllister et al., Proc. Natl. Acad. Sci.. USA. 89:5517-5521 (1992). 3) REC20 As described in Example 3B, the REC20 clone obtained from using a unique PCR amplification and screening strategy was 3.1 kb in length and had an open reading frame encoding a putative protein of 435 amino acids as εhown in Figure 5. Hydrophobicity analyεiε of the REC20 amino acid εequence predicted the presence of seven major membrane spanning domains. In addition, the receptor encoded by REC20 contains potential siteε for N-linked glycosylation, protein kinase C phosphorylation, and cAMP-dependent phosphorylation. REC20 also has transmembrane-εpecific amino acid reεidueε conserved among all biogenic amine receptorε (Aspl64, Pro254, Tyr262, Phe339, Trp343, Pro345, Trp374, Aεn383, Pro384) aε described by Trumpp-Kallmeyer et al., J. Med. Chem.. 35:3448-3462 (1992). REC20 exhibited highest identity, within the conserved transmembrane domains, with the Drosophila 5-HTdrol receptor (54%) as described by itz et al., Proc. Natl. Acad. Sci.. USA. 87:8940-8944 (1990). However, the entire REC20 sequence did not exhibit preferential identity to any known 5-HT receptor subgroup (5-HTdrol, 39%; 5-HT 1D , 39%; 5-HT , 37%; 5-HT 1E , 39%; 5-HT 5 , 33%) and is therefore classified as a novel 5-HT receptor, 5-HT 6 . The 5-HT 6 nomenclature has previously been given to a novel mouse receptor as described by Amlaiky et al., J. Biol. Chem.. • 267:19761-19764 (1992). B. Northern Analvsiε and Semi-Quantitative PCR 1) MR22 and REC17 MR22 and REC17 cDNAs were hybridized to blots containing RNA from rat brain regions and heart, liver and kidney to determine the tissue distribution of the mRNA encoding the respective serotonin receptorε. To perform Northern analyεiε, total RNA waε firεt isolated from frozen tisεueε of adult Sprague-Dawley ratε by extraction with guanidinium iεothiocyanate aε deεcribed by Chirgwin et al., Biochem.. 18:5294-5299 (1979). Oligo(dT)-cellulose chromatography, performed as described by Aviv et al., Proc. Natl. Acad. Sci.. USA. 69:1408-1412 (1972) was used to enrich for poly(A) + RNA. For RNA blots, 10 μg poly(A) * RNA was loaded per lane, except 1.5 μg for the medulla εample, and was subsequently resolved by electrophoresiε on a 1.2% agarose - 1.2 M formaldehyde gel, transferred to nitrocellulose membrane and hybridized to either 32 P-labeled MR22 cDNA (entire insert) or the 3' untranslated region of REC17 (nucleotides 1200 to 1719) . To confirm that similar amounts of intact RNA were loaded in each gel lane, blotε were stripped and hybridized with a [ 32 P]-cDNA probe for ubiquitously expresεed cyclophilin mRNA aε deεcribed by Danielson et al., DNA, 7:261-267 (1988). Detection of RNAs with either MR22 or REC17 cDNAs prepared in Example 1 required 2-3 week expoεures with 5 μg poly(A) + -enriched RNA sampleε. MR22 cDNA hybridized to three diεtinct RNAε with the approximate εizeε of 1.5, 1.8 and 3.0 kilobases (kb) that were detectable only in the hippocampal tiεsue sample. Given that the originally isolated MR22 PCR cDNA and the subsequent cDNA clone waε obtained from a hypothalamuε cDNA library, the hybridization to only hippocampal mRNA waε unexpected. The probable explanation iε that MR22 iε expreεsed in the hypothalamus but at a level below detection by RNA blotε; this is conεiεtent with the isolation of only one distinct MR22 cDNA clone from a hypothalamic cDNA library containing more than 10° recombinantε. In contraεt, REC17 detected RNA εpecieε with the approximate εizes of 3.8 and 4.5 kb in most regions of rat brain, with highest concentrations in hippocampus and hypothalamus, and lower concentrations in cortex, - Ill - thalamus, ponε, striatum and medulla. Neither MR22 nor REC17 mRNAs were detectable in heart, kidney and liver. The tissue distribution of MR22 and REC17 iε compared with the other serotonin receptors of thiε invention in Table 1 below. 2) MR77 The tissue distribution of MR77 expresεion could not be determined by Northern blotting because of the low expression of the mRNA. However, with the use of PCR and the fact that the MR77 gene contained an intron in its 5' untranslated region, semi-quantitative PCR could be performed to obtain tissue distribution information on MR77. Primers were deεigned so as to amplify MR77, producing a 563 base pair fragment from cDNA templates, but not from genomic DNA, as shown in Figure 4A. For this semi-quantitative PCR assay, two oligonucleotide primers were deεigned: one waε the inverεe complement of nucleotides 590 - 615 of MR77 cDNA (SEQ ID NO 1) and the other corresponded to the region of the cDNA 20 nucleotides upstream from the putative splice site. In a PCR assay, these primers amplify a 563 bp fragment from cDNA template, but not from genomic DNA. Poly A * RNA waε iεolated from a variety of dissected rat tissues including several brain regions. First strand cDNA was synthesized from 1 μg of poly A + RNA from each tissue uεing MMLV-Reverεe Tranεcriptaεe. Two μl of a 1/10 dilution of each cDNA waε uεed as template in a PCR reaction performed as described in Example 1A uεing the above deεcribed primerε for 30 amplification cycleε. Thirty cycles were determined to be within the linear amplification range under the conditions used. Equal aliquots (10 μl) of each PCR reaction were subjected to agarose gel electrophoresis. The resulting gel was denatured, neutralized, transferred to nitrocellulose membrane, and probed with a radiolabeled oligonucleotide complementary to nucleotides 364 - 385 of the MR77 cDNA clone (SEQ ID NO 1) , correεponding to nucleotides 257-278 of the genomic clone. Therefore, detection of the amplified products were expected to be diagnostic for the presence of MR77 mRNA. Equal amounts of cDNA made from mRNA extracted from a variety of rat tisεues were subjected to PCR and a major band migrating at approximately 570 base pairs was observed with some templates as εhown in Figure 4B. The 570 bp PCR product waε εubcloned and itε εequence was shown to be identical to the appropriate region of the MR77 cDNA. The MR77 PCR product was detected in approximately the following abundance: cortex = striatum = hippocampuε > thalamuε = pons > hypothalamus > cerebellum. The tiεsue distribution of MR77 is compared with the other serotonin receptors of thiε invention in Table 1 below. This distribution is consistent with known central nervous εyεtem terminal fieldε for εerotonergic pathwayε. The abundance of MR77 mRNA in the cerebral cortex waε estimated to be approximately 0.0001% of total mRNA, based on the comparison of the PCR product formed from cortex cDNA template to the product formed from known amounts of cloned MR77 DNA template. No PCR product was detected with liver, kidney, or heart cDNA templates. To show that the PCR products were not the result of amplification of genomic DNA, the same hippocampuε and cortex RNAε that were used to make cDNA template were additionally used aε templateε here but had not been reverse transcribed in this instance in PCR. These reactions did not yield any products as shown in lanes 12 and 13 in Figure 4B. 3) REC20 The anatomical distribution of REC20 mRNA expresεion in rat brain waε determined by northern blot analysis with the REC20 clone performed as described in Example 4B1) . The results that showed selective REC20 mRNA expression in the hypothalamus, thalamus, hippocampus, cortex, pons, and medulla. No mRNA expression was detected in the cerebellum, striatum, or peripheral tissueε εuch aε heart, liver, kidney, adrenal glands, testes, ovaries, or spleen. The tissue distribution of REC20 is compared with the other serotonin receptors of this invention in Table 1 below. C. Localization of mRNA Encoding Serotonin Receptors bv In Situ Hybridization 1) MR22 and REC17 In-situ hybridization εtudieε were performed to determine the cellular location of MR22 mRNAs within rat brain using a sensitive method as described by Strader et al., FASEB J.. 3:1825-1832 ((1989), the discloεure of which is hereby incorporated by reference. Free floating in situ hybridization was performed aε adapted from Gallet al., Science. 245:758-761 (1989). Coronal εectionε, 25 μm thick, from 4 young adult Sprague Dawley ratε were hybridized at 55°C for 16 hours with 1.5 x 10 7 cpm/ml c x 35 S-labeled single-εtranded RNA probes. Free floating sections were then digested with 4 μg/ml of RNaεe A in 50 mM Triε-HCl, 0.5 M NaCl, 1 mM EDTA (pH 7.5) for 1 hour at 37°C. Washes were performed in 50% formamide-0.5 x SSC containing 14 mM beta-mercaptoethanol at 60°C for three hours. Further washes were carried out in 0.1 x SSC-0.5% N-lauryl-sarkoεinate at 68°C for 1 hour. Sectionε were mounted on coated εlideε, dehydrated and exposed to Kodak XAR films for 5 days at room temperature. Autoradiography was performed by dipping slides in Ilford K4 emulsion diluted 1:1 with water, and exposing them with desiccant at 4°C for 5 weeks. Slides were developed in Kodak D19, counterstained and mounted in Permount. The most intense hybridization was detected in the hippocampus, medial and lateral habenular nuclei and raphe. Within the hippocampus, MR22 mRNA was excluεively detected in CAl region and subiculum; within CAl, MR22 hybridization was most prominent over the pyramidal layer. Very low silver grain densitieε, juεt above background, were found in piriform cortex and supraoptic nucleus of hypothalamuε. Thuε, the cellular localization of MR22 mRNA is consistent with the Northern blot data described in Example IB. The preliminary in situ hybridization data for REC17 is also consistent with the Northern blot data; REC17 mRNAs were detectable in many regions of the rat CNS (piriform cortex, hippocampus, amygdala, septum, and several thalamic nuclei. The ventral ascending εerotonergic pathway originating from the eεencephalic raphe nuclei innervateε a number of roεtral structureε including the medial habenula and hippocampuε, but also including the hypothalamuε, amygdala and several cortical regions. The significance of the observation that MR22 mRNAs in the hippocampuε were mostly restricted to CAl is unclear, although the rat 5-HT 1B receptor, which iε expressed in many areas of the brain, appears to be restricted in the hippocampus to synaptic terminalε of CAl efferents. See, Voigt et al., EMBO J.. 10:4017-4023 (1991). The tissue distribution of MR22 and REC17 is compared with the other serotonin receptors of this invention in Table 1 below. 2) REC20 To define the cellular distribution of REC20, the mRNA expresεion by in εitu hybridization in rat brain εliceε waε performed aε described in Example 4C1) . Expression was clearly noted in the thalamus, particularly in the ventrolateral, ventromedial, anteroventral, mediodorsal, and paraventricular thalamic nuclei. Hybridization was also detected in the hippocampus, predominantly in the CA3 region, the subicular complex, and the medial septal nuclei. Moderate expression was found in the anterior, lateral, and ventromedial hypothalamic nuclei. Hybridization waε also found in the suprachiasmatic nuclei of the anterior hypothalamus. In addition, REC20 mRNA was detectable in the piriform and cingulate cortices, as well as layers II and III of the neocortex. No hybridization was detected in the midbrain raphe nuclei. Thus, northern blot and in situ hybridization studies demonstrated 5-HT 6 REC20 mRNA expresεion in the thalamuε, hypothalamuε, cortex, ponε, and hippocampuε, but not in the cerebellum, heart, liver, or kidney. The compariεon of the tiεεue distribution of the four novel serotonin receptor proteinε of thiε invention iε εummarized in Table 1. Table 1 Region Rec20 MR77 MR22 Recl7 Cortex Yeε Yeε No Yeε Amygdala No No No Yes Hippocampuε Yeε Yeε Yeε Yeε Septum Yeε nd No Yes Thalamuε Yeε Yeε No No Hypothalamuε Yeε Yeε No No Raphe Nuclei No nd Yeε nd Cerebellum No No No No Heart No No No No Liver No No No No Kidney No No No No nd not determined D. LSD Binding Asεayε for Determining the Specificity of MR22. REC17, MR77 and REC20 Serotonin Receptorε To determine the ligand(ε) for MR22, REC17, MR77 and REC20 empirically, the four cDNAε were εeparately tranεfected into a eucaryotic expreεεion vector (pCMV4) and tranεiently transfected CosM6 cells as deεcribed in Exampleε IC, 2C and 3C. For the [ 125 I]-LSD binding aεεays, after the expresεed proteinε were purified and reεuεpended, [ 125 I]-LSD (NEN, 2200 Ci/mmol) binding was asseεεed in a 100 μl final volume and contained 0.02% aεcorbate, CosM6 membranes (15 μg protein), [ 125 I]-LSD (final concentration, l nM) , and various unlabeled test compounds identified in Table 2. Nonspecific binding was determined using 100 micromolar (μM) serotonin and typically was lesε than 10% of total diεintegrationε per minute (dpm) . Following 60 minuteε at 37°C, 2 ml of ice-cold 50 mM Tris-HCl were added to each tube and bound ligand was isolated on 0.1% polyethyleneimine-soaked GF/B glasε fiber filters, washed twice, and counted for radioactivity. Protein concentration was measured using the Bradford dye binding method (BioRad, Richmond, CA) . Binding data was analyzed using non-linear regression analysis. When tested in the above assay, broken cell preparations from transfected cellε, that have expressed either MR22, REC17, MR77 and REC20 recombinant serotonin receptor proteins, exhibited saturable binding for [ 125 I]-LSD, a non-selective serotonergic ligand. To relate each of the serotonin receptors to known members of the 5-HT receptor family, the ability of selective 5-HT agonistε and antagonists were measured for their ability to displace LSD from the membrane preparationε. The assays measuring IC50 values for competition with 15 I-LSD (nM) were performed as described above and the data is summarized in Table 2 below. Table 2 Ligand Rec20 MR77 MR22 Recl7 8-OH-DPAT 97 >1000 >1000 >1000 5-CT 0.8 >1000 285 20.4 Methysergide 32 14 >1000 310 Ergotamine 33 55 22 10 Metergoline 17 535 >1000 >1000 Meεulergine 17 >1000 >1000 >1000 5-HT 9 70 1613 380 Methiothepin 1.3 >1000 176 45 Sumatriptan >1000 67 >1000 >1000 Ritanεerin 60 - - - Clozapine 48 - - - Yohimbine >1000 570 >1000 >1000 Pindolol >1000 ~ ™ ~ The binding of radiolabeled LSD to MR77 iε εenεitive to sumatriptan, a 5-HT1D agonist , but insenεitive to 5-carboxyamidotryptamine (5-CT) , a mixed agoniεt, and 8-OH-DPAT, a 5-HTi A agoniεt. The pharmacological profile of MR77 iε εimilar to that of the 5-HT 1E receptor. MR22 and REC17 have εimilar pharmacological profileε which do no readily fit to any pharmacologically defined 5-HT receptorε which have been previouεly deεcribed. Both receptorε are εenεitive to ergotamine, 5-CT and methiothepin but insensitive to εumatriptan and 8-OH DPAT. REC20 haε a pharmacological profile that iε unique in that the binding of radiolabeled LSD iε diεplace by 5-HT 1A agoniεtε 8-OH DPAT and 5-CT but is alεo εenεitive to the 5-HT 2 antagonist ketanserin. These pharmacological profileε in conjunction with the amino acid reεidue sequence as described below allows for the classification of the four novel serotonin receptors of this invention into three new subfamilieε of the εerotonin receptor family. E. Dendrogram Claεεification of the Novel Serotonin Receptor Proteinε Based on Amino Acid Residue Sequence Historically, the claεεification of serotonin receptors (5-HT) has been based on their pharmacological properties as reviewed in Frazer et al., Ann. Rev. Pharmacol. Toxicol.. 30:307-348 (1990) . Thus, S-H^-like receptors have been classified aε (i) potently antagonized by methiothepin and/or methysergide, (ii) not antagonized by molecules binding specifically to 5-HT 2 , and (iii) potent agonism to 5-CT (greater than or equal to 5-HT) . See, Bradley et al., Neuropharm.. 25:563-576 (1986) . With the advent of molecular cloning of 5-HT receptors, their classification has changed from being based purely on pharmacological criteria to a more structurally based definition. Hartig, TIPS. 10:64-69 (1989) and Peroutka, Neuropharm.. 31:609-613 (1992) have suggested that the receptor nomenclature for 5HT receptors be primarily based on amino acid sequence. The use of primary structure to catalogue 5-HT receptors is appropriate aε it allowε for an abεolute identification of each 5-HT receptor. The relationεhipε among the known G-protein coupled εerotonin receptorε iε graphically illuεtrated aε a dendrogram aε εhown in Figure 6. The dendrogram mapping of the novel serotonin receptors of this invention are described below. 1) MR22 and REC17 Two of the four novel εerotonin receptorε of this invention, MR22 and REC17, have no greater sequence identity to the known 5-HT receptors than to other previously cloned cationic binding receptors. The amino acid sequences of REC17 and MR22 were compared to all known 5-HT receptors, using the program PILEUP (GCG, Univ. of Wisconsin) which ranked (by pairwise εequence identity) each receptor in relation to the otherε being examined. When the relationships were plotted as a dendrogram aε shown in Figure 6, in which sequence identity is inversely proportional to the length of the horizontal line, REC17 and MR22 were seen to form a diεtinct εubfamily between that of the SH^-like (5HT 1A/B/D/E and 5HT 2 -like familieε (5HT 1c/2 ) . Plassat et al., EMBO J.. 11:4779-4786 (1992) have recently reported identification of the apparent mouse homolog of REC17, which they have referred to as 5-HT 5 . Because the primary structures of REC17 and MR22 are diεtinct from other known 5-HT receptorε, REC17 and MR22 have been designated as novel serotonin receptors, 5-HT 5a and 5-HT 5β , reεpectively. 2) MR77 The rat MR77 cloneε and its human homolog correspond to a novel 5-HT receptor, more closely related in sequence to the recently cloned human S31 receptor (5-HT 1E ) than any described 5-HT receptor but clearly a new member of the 5-HT., receptor family. The data presented in the preceding Examples on MR77 demonstrate that the MR77 gene encodes a novel 5-HT receptor protein that iε expressed predominantly in the central nervous syεtem. The mRNA distribution pattern in the brain iε conεistent with terminal fields for some serotonergic neuronε. The identification of receptor geneε haε recently outpaced traditional pharmacological identification. It haε therefore become increaεingly difficult to claεεify novel receptor gene products on a basis other than amino acid sequence. Given that the sequence of MR77 is moεt similar to 5-HT 1E , the MR77 gene of this invention has been identified as another member of the 5-HT 1E receptor subgroup. The 5-HT 1B and 5-HT 10 receptors and the MR77 and 5-HT 1E receptors form distinct subfamilies, more similar to each other collectively than to 5-HT 1A , as determined by amino acid εequence comparisons. This may be due in part to the longer putative third intracellular loop in 5-HT 1A compared to the other receptors. Previously cloned 5-HT receptors have fallen into either 5-HT, or 5-HT 2 families by both significant sequence identity and pharmacological profiles. 3) REC20 As described in Example 3, degenerate PCR was used to target and identify a novel G-protein coupled receptor. The isolated clone was designated as REC20 and was determined to have a nucleotide sequence 3.1 kb in length which exhibited an open reading frame encoding a putative protein of 435 amino acids (Figure 5) . REC20 exhibited highest identity, within the conεerved tranεmembrane domainε, with the Droεophila 5-HTdrol receptor (54%) . However, the entire REC20 εequence did not exhibit preferential identity to any known 5-HT receptor εubgroup and iε therefore classified as a novel 5-HT receptor, 5-HT 6 . This grouping is graphically illustrated as a dendrogram in Figure 6 that includes three other novel serotonin receptor clones of this invention which have been identified as the putative 5-HT 5A and 5-HT 5B receptorε, REC17 and MR22, reεpectively, and the 5-HT 1E -like (5-HT 1F ) receptor deεignated MR77. From this analysiε, REC20 waε determined to repreεent a separate clasε of 5-HT receptorε, with diεtant εimilarity more to 5-HT and 5-HTdrol receptors than other subclaεεeε. It iε perhapε εignificant that REC20 bearε little reεemblance to the 5-HT 5 receptors to which it was targeted. This finding speaks to the power of degenerate PCR, whereas this discovery would not have occurred with traditional low-stringency hybridization screening. In summary, the molecular cloning and the pharmacological profile described herein of these four novel serotonin receptorε, MR22, REC17, MR77 and REC20, will provide pharmacologiεtε to εtudy each receptor in iεolation; thiε in turn will allow the development of rational drug deεign, thereby leading to successful therapeutic reagents. 5. Preparation of Synthetic Polypeptides of Novel Serotonin Receptors A. Synthesis of Polypeptideε Synthetic polypeptides, listed in Table 3 and 4 below, were derived from the derived amino acid residue sequence of the novel serotonin receptor proteinε, MR22, REC17, MR77 and REC20, prepared in Exampleε 1-3. Polypeptideε for diagnoεtic uεe are liεted in Table 3 while polypeptideε for uεe in generating blocking reagent antiεera are liεted in Table 4. Methodε for the preparation of synthetic polypeptides corresponding to amino acid residue sequences of portions of naturally occurring proteins translated from brain-specific mRNAs is described in US Patent 4,900,811, the discloεure of which is hereby incorporated by reference. The polypeptides of this invention were produced by the simultaneous multiple peptide syntheεiε method uεing the solid-phase technique described by Houghten, Proc. Natl. Acad. Sci.. USA. 82:5131-5135 (1985). The peptides are hereinafter referred to by their corresponding serotonin receptor and their SEQ ID NO as listed in Table 3 and 4. In addition, the polypeptides listed in Table 4 are referred to by the regions of the serotonin receptor protein from which the polypeptides were derived. All polypeptides were synthesized in the carboxy-terminal amide form. The synthesized peptides were then analyzed by reverse phase high performance liquid chromatography (HPLC) on a Vydac C-18 column (Alltech Associates, Inc., IL) with a 0-60% acetonitrile linear gradient in 0.1% trifluoroacetic acid. Peptides were then purified to homogeneity by preparative HPCL using optimal conditions suggeεted by the analytical chromatography. Amino acid compositions and concentrations of isolated peptides were determined by subjection to 24 hour hydrolysiε in 6 N HC1 in evacuated tubeε at 110 degreeε Celsius (110°C) and subsequent analysis on a Beckman Model 6300 High Performance Analyzer. Purified peptides were separately resuεpended in diεtilled water to form a diεεolved peptide εolution prior to uεe aε compoεitionε in the methodε of thiε invention. Table 3 SEQ Serotonin Receptor ID NO AMINO ACID RESIDUE SEQUENCE MR77: 36 MIKEELNGQVLLESGEK 37 HSTVKSPRSELKHEKSWR MR22: 38 WTITRHLQYTLRTRRR 39 WPLPATTQAKEAPQESETV 40 RATVAFQTSGDSWREQKEKR 41 KNYNNAFKSLFTKQR REC17 42 VSPIPEAVEVKDASQHPQM 43 RSYSSAFKVFFSKQQ REC20: 44 RKSAAKHKFPGFPRVQPES 45 PEVGRGLQDLSPDGGAHPWS 46 SRLLKHERKNISIFKREQK Table 4 SEQ Serotonin Receptor ID NO AMINO ACID RESIDUE SEQUENCE* MR22 N-terminus 47 MEVCNLSGATPGIAFPPGPESCSDSPSSG- RSMGSTPGGLILSGREPPFSAFT EC loop 1 48 PLSLVSELSAGRRWQLGRSLCHVWISFD EC loop 2 49 APLLFGWGEAYDARLQRCQVSQEPSYAVFSTC EC loop 3 50 WIPFFLTELVSPLCACSLPPIWKSIFLWLG C-terminus 51 KNYNNAFKSLFTKQR REC17 N-terminuε 52 MDLPINLTSFSLSTPSTLEPN- RSLDTEALRTSQSFLSAFR EC loop 1 53 PLSLVHELSGRRWQLGRRLCQLWIAL EC loop 2 54 APLLFGWGETYSELSEECQVSREPSYTVFSTV EC loop 3 55 VTELISPLCSWDIPALWKSIFLW C-terminuε 56 RSYSSAFKVFFSKQQ MR77 N-terminuε 57 MDFLNSSDQNLTSEELLNRMPSK EC loop 1 58 MPFSIVYIVRESWIMGQGLCDLWLSVD EC loop 2 59 FISMPPLFWRHQGNSRDDQCIIKHD- HIVSTIYSTFG EC loop 3 60 WLPFFVKELWNICEKCKISEEMSNF C-terminuε 61 YTIFNEDFKKAFQKLVRCRN HumMR77 N-terminus 62 MDFLNSSDQNLTSEELLNRMPSK EC loop 1 63 MPFSIVYIVRESWIMGQWCDIWLSVD EC loop 2 64 FISVPPLFWRHQGTSDDECIIKHD- HIVSTIYSTFG EC loop 3 65 WLPFFVKELWNVCDKCKISEEMSNF C-terminus 66 YTIFNEDFKKAFQKLVRCRC REC20 N-terminus 67 MMDVNSSGRPDLYGHLRSLILPEVG- RGLQDLSPDGGAHPWSSWMPHL- LSGFLEVTASPAPTWDAPPDNVS- GCGEQINYGRVEK EC loop 1 68 MPFVSVTOLIGGKWIFGHFFCN- VFIAMDVMCC EC loop 2 69 TLPPLFGWAQNUNDDKVC- LISQDFGVTIYSTAVAF EC loop 3 70 FTVCWLPFFLLSTARPFIC- GTSCSCIPLWVERTCLW C-terminus 71 FFNRDLRTTYRSLLQCQYRNINR- KLSAAGMHEALKLAERPERSEFVL EC = extracellular Hum = human clone * = The sequence of the polypeptides is listed in the ord it appears in the serotonin molecule from N- to C- terminuε The εynthetic serotonin receptor-derived polypeptides prepared as described herein are then used in ligand binding asεayε to determine the polypeptide's binding characteristics. The binding assays are performed as described in Example 4D with radiolabeled LSD used as a serotonin analog for binding to serotonin receptors. 6. Preparation of Polyclonal Antisera to Synthetic Polypeptideε A. Preparation of Immunogen For preparation of a peptide immunogen, the synthetic polypeptides listed in Table 3 were prepared as described in Example 5. The preparation of polypeptide antisera to synthetic polypeptides haε been described in US Patent 4,900,811, the disclosure of which iε hereby incorporated by reference. The synthesized polypeptides were separately coupled to keyhole-limpet-hemocyanin (KLH) (Sigma, St. Louis, MO) using the heterobifunctional crosslinking agent, N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP) (Pierce Biochemicals, Rockford, IL) . For the coupling procedure, 80 μl of 10 mg/ml SPDP diεεolved in di ethylformamide were admixed dropwiεe to 400 μl 15 mg/ml KLH in 0.1 M phoεphate, 0.1 M NaCl at pH 8.5 under continuouε εtirring conditionε for 30 inuteε at 22°C in order to form SPDP-activated KLH. The reεultant SPDP-activated KLH waε then extenεively dialyzed at 4°C againεt a buffered solution of 0.1 M phosphate and 0.1 M NaCl at pH 7.4 in order to remove uncoupled SPDP. Six mg of the prepared polypeptides were first dissolved in 2 ml of 0.1 M phosphate and 0.1 M NaCl at pH 7.4 and then admixed with SPDP-activated KLH prepared above under continuous stirring conditions. The degree of coupling of the individual polypeptides with KLH waε monitored by diluting an aliquot of the mix 1:100 at time zero, and each hour thereafter, and measuring the release of pyridine-2-thione at 343 nm in a spectrophotometer. The end point of coupling was determined to be an increase of 0.2 in absorbency, or upon visualization of precipitate at which point KLH conjugates peptide was formed, and designated polypeptide-KLH immunogen. B. Immunization and Collection of Polyclonal Antisera To form anti-peptide antibodies, the separate polypeptide immunogens prepared in Example 6A were emulsified using Adjuvant Complete Freund (DIFCO Laboratorieε, Detroit, MI) for the first injection and Adjuvant Incomplete Freund (DIFCO) for all subsequent injections according to the manufacturer's instructions, and the polypeptide-KLH immunogens were incorporated into the emulsion at a concentration of 2 mg/ml. One-half ml of each prepared emulsion was injected subcutaneously into each of two New Zealand white rabbits after pre-immune serum samples were collected. The emulsion was injected into rabbitε three timeε at weekly interyalε following the injection protocol as detailed. Two weeks after the last injection, blood εampleε were collected to check antibody titer against the specific polypeptides uεed as immunogens by the ELISA asεay deεcribed below in Example 6C. The collected blood εampleε were εtored at 4°C for 12 hourε, after which the εampleε were centrifuged at 3000 x g for 20 minuteε. The resultant supernatant containing anti-peptide antibodies was collected, designated polyclonal anti-polypeptide antibodies and stored at -20°C. The polypeptides in Table 4 are also separately prepared as immunogens by conjugation with KLH as described in Example 6A. Immunization of separate rabbits for the production of antisera against each of the peptides listed above is performed as described herein. The resultant antisera are then screened by ELISA as described below. C. ELISA to Screen Antisera Immunoreactivitv The polypeptide antibody titers and immunospecificity in sera collected from rabbits in Example 6B were determined in an enzyme-linked-immunosorbent-assay (ELISA) as described below. The antigens uεed in the ELISA included the immunizing polypeptideε. To determine the immunospecificity of the rabbit antisera obtained in Example 6B, ELISA asεayε were performed. Briefly, 50 μl of 50 μM concentrationε of the polypeptideε prepared in Example 5 and listed in Table 3 in a buffer consiεting of 0.05 M sodium carbonate (Na 2 C0 3 ) and 0.02% NaN 3 at pH 9.0 were separately admixed into the wells of microtiter plates. The plates were maintained at 37°C for 1 hour to permit the antigenε to become operatively affixed to the well wallε. After washing the antigen-coated wells with TBS, the wells were blocked with 250 μl/well of 10% bovine serum albumin (BSA) (Sigma) in TBS for 1 hour at 22°C. The blocking solution waε then removed and the wellε were subsequently washed five times with 250 μl/well of maintenance buffer (0.05 M Tris-HCl, 0.1 M NaCl, 0.02% NaN 3 , 1 mg/ml BSA, 5 mM CaCl 2 , 0.01% Tween 20 at pH 7.4). Fifty μl of rabbit nonimmune or specific antiserum serially diluted in maintenance buffer were then admixed to the washed wells to form an immunoreaction admixture, that was maintained for 1 hour at 37°C to allow formation of a solid-liquid phase immunoreaction products. The wells were then washed 3 times with maintenance buffer followed by admixture of 50 μl of 1.0 μg/ml of secondary antibody (polyclonal biotinylated goat-anti-rabbit-IgG) (Pierce Chemicals, Rockford, IL) diluted in maintenance buffer to each well for the detection of immunoreactant products. The plates were maintained for 1 hour at 37°C after which time the secondary antibody solution was removed. After washing the wells as described above, 50 μl of 1.0 μg/ml streptavidin-alkaline-phosphatase (Pierce Biochemicalε) in maintenance buffer were admixed into each well and maintained for 30 minuteε at 37C. Detection of specific immunoreaction products was obtained by admixture of 150 μl/well of 5 mg/ml p-nitrophenylphosphate (PNPP) (Pierce Biochemicals) in 0.1 M diethanolamine and 0.02% NaN 3 at pH 9.0 followed by measurement of the change in absorbance at 405 nm over time using the EL312 Microplate Bio-Kinetics Reader and the KinetiCalc Software Program (Biotek Inεtrumentε, Inc., VT) . Nonεpecific binding waε considered as the measured absorbance in 10% BSA blocked wells which served aε negative controlε without the preceding coating of a specific protein or peptide. Under the described conditions, nonspecific binding never exceeded more than 5% of the εpecific binding. Rabbit anti-polypeptide antisera which exhibited immunoreactivity that produced an optical density change at 405 nm of greater than 20 delta per minute using the kinetic program as compared to the immunoreactivity of pre-immune serum toward the immunogen polypeptides was selected for uεe as separate anti-peptide antibodies, and also selected for further purification below. Rabbit antisera, that are obtained in Example 6B against the polypeptides in Table 4 are screened for immunoreactivity to the respective polypeptide immunogen aε described above. Rabbit antisera which exhibited significant immunoreactivity as compared to the pre-immune sera toward each of the polypeptide immunogens are further purified and analyzed as described below. D. Purification of Anti-Polvpeptide Antibodies Purification of the IgG fraction from the rabbit antisera collected above, which showed εignificant reactivity towardε the immunizing polypeptideε in Table 3, was conducted by ammonium-sulfate precipitation (0-45%) , followed by purification of IgG on an ion-exchange Mono Q column (Pharmacia LKB, Piεcataway, NJ) connected to a faεt protein liquid chromatography (FPLC) εystem (Pharmacia) . Immunoaffinity purification of the pooled immunoreactive IgG-fraction waε performed by paεsing approximately 100 mg of the IgG over a 5 ml column containing 3 mg of individual polypeptideε prepared in Example 5 coupled to Sepharoεe 4B (Pharmacia) according to manufacturer• instructions. After a thorough washing of the column with 5 column volumes of 0.05 M Tris-HCl and 1 M NaCl at pH 7.4 to remove unbound antibodieε, the bound IgG waε eluted with two column volumeε of 0.1 M glycine-HCl at pH 2.5. The eluted protein for each antibody waε monitored by abεorbance at 280 nm and the IgG concentrationε determined from the extinction coefficient of 13.5. The eluted IgG waε immediately dialyzed against TBS-Az, concentrated against 50% sucrose for approximately 3-4 hours and once more extensively dialyzed against TBS-Az to a final concentration of 3-4 mg/ml. Analysis by 4-15% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of reduced and non-reduced samples revealed greater than 95% pure IgG. The immunoaffinity-purified anti-polypeptide antibodies prepared herein were used as diagnostic reagents in the methods of this invention. Purification of the IgG fraction from the rabbit antisera collected above, which showed significant reactivity towards the immunizing polypeptides in Table 4, is conducted following the purification procedures described above. The immunoaffinity-purified anti-polypeptide antibodies prepared herein are used as blocking reagents in the methods of this invention. 7. Analysiε of the Serotonergic Aqentε on Suprachiaεmatic Neuronal Activity The effectε of εerotinergic agentε on the neuronal activity aε meaεured againεt circadian time in the suprachiasmatic nucleus (SCN) were measured. The procedures used in measuring the circadian time involving εlice preparation and maintenance, electrophyεiological recordingε, and data analyεiε were performed aε described by Prosser et al., J ^ _ Neuroεci. , 9:1073-1081 (1989). Slice treatment consisted of stopping perfusion and replacing bath medium for 1 hour with medium containing no additional compounds (=control) or 8-OH-DPAT. In blocking experiments, bath medium was first replaced for 15 minutes with perfuεion medium containing either pindolol or ritanserin (dissolved in 100% ethanol and then diluted to the proper concentration) , followed by replacement for 1 hour with medium containing 8-OH-DPAT and either pindolol or ritanserin, followed by an additional 15 minute treatment with medium containing pindolol or ritanεerin. Thiε was followed by the normal perfusion medium. The results of testing the effects of serotonergic agents on the SCN neuronal activity are shown in Figure 7. Evident from the bar graphs is the alteration of neuronal activity as measured in Hz over time by the serotonin receptor agonist 8-OH-DPAT. This data indicate that the agonist induces a phaεe advance of about 2-3 hourε in the circadian rhythm of spontaneous neuronal activity in the SCN (at CT Λ ) . In addition, the antagonist ritaserin blocks the 8-OH- DPAT-dependent phase shift whereas the antagonist pindolol has no effect. This pharmacological profile of the εerotonin-induced phaεe εhift iε unique to REC20; no other known 5-HT receptorε exhibit thiε profile. Theεe reεultε indicate that the therapeutic reagentε deεcribed herein which are εpecific for 5-HT 6 are useful for inhibiting the receptor, and for resetting the phase of the circadian rhythm. The phase adjustment of the 24-hour circadian clock has applications in treatment to avoid or ablate jet lag, adjust the clock in the work force where there are abnormal or changing work shifts, and for synchronization of the clock in the elderly or others where there is a dysynchronization of the clock. 8. Screening for Serotonin Receptor Agonists and Antagonists Four new serotonin receptors have been discovered as described in this invention for the neurohormone serotonin, bringing the total number known to about 12. More than 12, but fewer than 25, receptors for serotonin are probably expressed by humans and other animals. Agonism or antagonism at any one of these receptors initiates physiological sequelae distinct from action at any of the others due to differences in each particular receptor with respect to 1) its anatomical sites of expression, 2) its subcellular sites of expresεion, and 3) the second messenger systems to which the receptor couples. Pharmaceutical compositions that discriminate amongst the receptors, especially those selective for a single receptor type, would be efficacious in treatment of diseases selectively involving systemε utilizing that certain receptor while initiating fewer or no side effects due to agonism or antagonism at other serotonin receptor types unrelated to the disease state. Therefore, identifying compounds that are selective agonistε or antagoniεtε for the 4 new receptors, as well as for all other serotonin receptors iε of great intereεt and εignificance. Preεently known εerotonin receptor-binding compoundε have fairly broad εpectra of binding; that iε, they bind to many, but uεually not all, receptor subtypes. Three general strategies can be used to identify novel selective compounds. Each strategy ultimately requires screening membrane preparations containing individually each of the 4 novel receptors as well as other receptors. Strategy l relies on the εyεtematic production of compoundε that differ εlightly in their chemical εtructureε from compoundε already known to bind. Once εyntheεized, each new compound iε εcreened for itε ability to bind εelectively to membraneε carrying any of the expreεsed receptors. Newly identified compounds that bind are subsequently examined in functional studies to determine 1) whether they have agonistic or antagonist effects, 2) their toxicology, 3) their effectivenesε in crossing the blood-brain barrier, and 4) their effect upon physiological function, especially as it concernε εyεtemε utilizing εerotonergic tranεmission in diseaεed patientε. Strategy 2 involveε εcreening compoundε not necessarily known to interact with serotonin receptors for their ability to interact with a particular receptor of interest, for example REC20. Compoundε εhown to bind to REC20 are εubsequently studied for their abilities to bind to other receptors, and examined according to the list of four issueε liεted in the preceding paragraph. REC20-binding compoundε would additionally serve aε lead compoundε for the development of compoundε with related molecular εtructureε that might have more desirable selectivity, affinity, permeability, solubility, toxicology, efficacy in treatment. Strategy 3 involves a multiplex screening of all compoundε examined in Strategy 2 for their abilitieε to interact with membraneε containing any of the cloned receptors. Whereas in Strategy 2, if an interest arises primarily in pharmacologically active ligands such aε REC20 becauεe REC20 iε likely to be involved in circadian rhythmicity and sleep and new compounds need to be identified that are selective for these physiological phenomena. Strategy 3 takes the view that any compound that iε a εelective agonist/antagonist for any of the several serotonin receptors has selective efficacy for treatment of particular but not yet specified diseaseε. The new receptor-selective ligands identified are tested for their physiological effects and the outcomes used to define a list of candidate applications. Many of these candidate applications are foreseen because of the sites of expression of the various receptor types and the differential activities of known broad-range serotonin receptor-selective pharmaceuticals. The foregoing written specification iε conεidered to be sufficient to enable one skilled in the art to practice the invention. Indeed, various modificationε of the invention in addition to thoεe shown and described herein will become apparent to those skilled in the art from the foregoing description and fall within the scope of the appended claims. SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANT: (A) NAME: The Scripps Research Institute (B) STREET: 10666 North Torrey Pines Road (C) CITY: La Jolla (D) STATE: CA (E) COUNTRY: USA (F) POSTAL CODE (ZIP) : 92037 (G) TELEPHONE: 619-554-2937 (H) TELEFAX: 619-554-6312 (ii) TITLE OF INVENTION: HUMAN SEROTONIN RECEPTORS, DNA ENCODING THE RECEPTORS, AND USES THEREOF (iii) NUMBER OF SEQUENCES: 73 (iv) COMPUTER READABLE FORM: (A) MEDIUM TYPE: Floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING SYSTEM: PC-DOS/MS-DOS (D) SOFTWARE: Patentin Release #1.0, Version #1.25 (EPO) (v) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: PCT/US 94/ (B) FILING DATE: 15-MAR-1994 (vi) PRIOR APPLICATION DATA: (A) APPLICATION NUMBER: US 08/031,538 (b) FILING DATE: 15-MAR-1993 (2) INFORMATION FOR SEQ ID NO:l: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2226 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:l: GGTTCCCAGT GTGCAGGCAT CAGTCCCCAG TTCTGCAGGC GGTTGGTTAC TCTGAAGACC 60 ACAAAGAGAC TGGGAGAGGT TGATGCGCTG GACAAAGCTA GACTAAGGAG TCTCAACTGG 120 AAAAAAGGGT CTACGAAAAC CTCAAAAAAG AAGCGCCTAC AGTTTGGAAA AAGAACAAAG 180 GTGGCGCGGC TTAGACTTCT TTTTGTGTTG CTGGGCTCGC GCAGTGCCCC TCCTGCCTCG 240 CCACCTAACC ACAGTTCATG CAATCACGGG CACATCTGCC AGAGAGCCCG AGTCCCTGAA 300 CAATGGAAGT CTCTAACCTC TCAGGCGCCA CCCCTGGCAT TGCCTTTCCT CCGGGACCCG 360 AGAGCTGCAG TGACAGCCCA AGTTCCGGCA GAAGCATGGG ATCCACCCCA GGGGGGCTCA 420 TCTTGTCCGG CCGCGAGCCG CCCTTCTCTG CCTTCACCGT ACTCGTGGTA ACTCTACTGG 480 TGTTGCTGAT CGCTGCCACT TTCTTATGGA ATCTGCTAGT TCTGGTGACT ATCCTGCGCG 540 TCCGCGCCTT CCACCGTGTG CCACATAACT TGGTAGCCTC GACCGCCGTC TCGGACGTCC 600 TGGTGGCGGC TCTGGTGATG CCACTGAGCC TGGTGAGCGA GTTGTCGGCT GGGCGACGTT 660 GGCAGCTGGG CAGGAGTCTG TGCCACGTGT GGATCTCCTT CGACGTGTTG TGCTGCACAG 720 CCAGCATCTG GAACGTGGCG GCCATCGCCC TGGATCGCTA CTGGACTATC ACGCGCCACC 780 TGCAGTACAC GCTGCGCACC CGGCGCCGCG CTTCAGCACT TATGATCGCG ATCACCTGGG 840 CACTGTCCGC CCTCATCGCG CTCGCCCCGC TGCTCTTTGG CTGGGGCGAA GCCTACGATG 900 CTCGGCTGCA GCGTTGCCAG GTGAGCCAGG AGCCTTCGTA CGCCGTCTTC TCCACCTGCG 960 GAGCTTTCTA CGTGCCTCTG GCCGTGGTGC TCTTCGTCTA CTGGAAGATA TACAAAGCCG 1020 CCAAGTTTCG ATTCGGCCGC AGACGGCGGG CGGTAGTGCC CCTGCCCGCC ACCACGCAGG 1080 CAAAGGAAGC ACCTCAGGAG TCTGAGACGG TATTCACCGC GCGTTGCAGA GCGACAGTGG 1140 CCTTCCAGAC AAGTGGAGAC TCCTGGCGGG AGCAGAAGGA GAAGCGAGCC GCCATGATGG 1200 TGGGGATCTT GATCGGTGTG TTTGTGCTGT GCTGGATCCC CTTCTTCCTG ACGGAGCTCG 1260 TCAGCCCGCT CTGCGCCTGC AGCCTGCCAC CCATCTGGAA AAGCATATTC CTGTGGCTTG 1320 GCTATTCAAA TTCGTTCTTC AATCCCTTAA TCTACACGGC CTTTAATAAG AACTACAACA 1380 ATGCCTTCAA GAGCCTCTTT ACTAAGCAGA GATAAGCAGG GCTGGGGAGA TAAAAAGGAA 1440 GACCGGGGAA GAGAAAGGGG ATCTGCCGTC CTCATTTCAC CAGAGACCTG GGGGCTTCTC 1500 CCCGCCGCCC ACACCCCCCT AACGACACTC CAGAAATCAC ACCGTAGGGC CTGGAATGTT 1560 GAGTTCTCAC GAAGGTAGAC AACGGTTTGG CAAATACATC CATGCCTTCT ACGCGTCGTG 1620 ACAGACATTG CTAGTGAATT GTGCTACATT TCTGCACCAG GCAGGAACCC CGCCAAACCC 1680 TTTCCGGGTG TATTTTAGGT ATTATTGCTC ATTTGTCAGA CTCCACATGT GGCAGAGTTG 1740 ATTTGCTTTT GCGTTAGTAC TATGTCCCTC AGTGAGGGTC TCTTGGGGCT CTCCTGAGAC 1800 TGACTCCTTG ACATAGCCTC TCCTCTACCC CTTATCCATC AGAGCACTTT ACCTTTCTTA 1860 GCCTCACACA GGACCTCCAC AAGGCAATGA TTCTCAGTTT AGGAAGAGAT GTCCTCGCCT 1920 GAAGCTTTGT TAAAAAGTGT TCCACACAGA CGTCGTCAAG ATGGCTCAGT AGAGGGGGTT 1980 GGGGATTTAG CTCAGTGGTA GAGCCCTTGC CTAGGGAGCG CAAGGCCCTG GGTTCGGTCC 2040 CCAGCTCCGA AAAAAAGAAC CAAAAAAAAA AAAAAAAAAA AAAAAAGATG GCTCAGTAGA 2100 TGAAGGCGCC TGTCCCCAAG CCTGGTGGCC TGCTTTTGAG ATACATGTAA TGGAAGGAAA 2160 TAAAATGATT GCAAGTTGTC TCTGACCTCC AGATATGTGC CATCAGCCCT CTCCCCCATG 2220 TGCACA 2226 (2) INFORMATION FOR SEQ ID NO:2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 370 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2: Met Glu Val Cys Asn Leu Ser Gly Ala Thr Pro Gly He Ala Phe Pro 1 5 10 15 Pro Gly Pro Glu Ser Cys Ser Asp Ser Pro Ser Ser Gly Arg Ser Met 20 25 30 Gly Ser Thr Pro Gly Gly Leu He Leu Ser Gly Arg Glu Pro Pro Phe 35 40 45 Ser Ala Phe Thr Val Leu Val Val Thr Leu Leu Val Leu Leu He Ala 50 55 60 Ala Thr Phe Leu Trp Asn Leu Leu Val Leu Val Thr He Leu Arg Val 65 70 75 80 Arg Ala Phe His Arg Val Pro His Asn Leu Val Ala Ser Thr Ala Val 85 90 95 Ser Asp Val Leu Val Ala Ala Leu Val Met Pro Leu Ser Leu Val Ser 100 105 110 Glu Leu Ser Ala Gly Arg Arg Trp Gin Leu Gly Arg Ser Leu Cys His 115 120 125 Val Trp He Ser Phe Asp Val Leu Cys Cys Thr Ala Ser He Trp Asn 130 135 140 Val Ala Ala He Ala Leu Asp Arg Tyr Trp Thr He Thr Arg His Leu 145 150 155 160 Gin Tyr Thr Leu Arg Thr Arg Arg Arg Ala Ser Ala Leu Met He Ala 165 170 175 He Thr Trp Ala Leu Ser Ala Leu He Ala Leu Ala Pro Leu Leu Phe 180 185 190 Gly Trp Gly Glu Ala Tyr Asp Ala Arg Leu Gin Arg Cys Gin Val Ser 195 200 205 Gin Glu Pro Ser Tyr Ala Val Phe Ser Thr Cys Gly Ala Phe Tyr Val 210 215 220 Pro Leu Ala Val Val Leu Phe Val Tyr Trp Lys He Tyr Lys Ala Ala 225 230 235 240 Lys Phe Arg Phe Gly Arg Arg Arg Arg Ala Val Val Pro Leu Pro Ala 245 250 255 Thr Thr Gin Ala Lys Glu Ala Pro Gin Glu Ser Glu Thr Val Phe Thr 260 265 270 Ala Arg Cys Arg Ala Thr Val Ala Phe Gin Thr Ser Gly Asp Ser Trp 275 280 285 Arg Glu Gin Lys Glu Lys Arg Ala Ala Met Met Val Gly He Leu He 290 295 300 Gly Val Phe Val Leu Cys Trp He Pro Phe Phe Leu Thr Glu Leu Val 305 310 315 320 Ser Ala Leu Cys Ala Cys Ser Leu Pro Pro He Trp Lys Ser He Phe 325 330 335 Leu Trp Leu Gly Tyr Ser Asn Ser Phe Phe Asn Pro Leu He Tyr Thr 340 345 350 Ala Phe Asn Lys Asn Tyr Asn Asn Ala Phe Lys Ser Leu Phe Thr Lys 355 360 365 Gin Arg 370 (2) INFORMATION FOR SEQ ID NO:3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2155 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3: GCTCCGGACT CTCACTGGGT GGAGACTGAG GTCAGGTTCT TGGCTCTTGG CAGAATCCTC 60 TCCACTGGCC AGCGGTTGCA AACATCTAAA TTGACTTCAG TGAACTCGGT GACTGCATTG 120 AGTCTAAACG CAGGTGTGCT GGGCCAGCAA TGGATCTGCC TATAAACTTG ACCTCCTTTT 180 CTCTCTCTAC TCCCTCCACT TTGGAACCTA ACCGCAGCTT GGACACGGAA GCCCTGCGCA 240 CTAGTCAGTC TTTTCTCTCA GCTTTCCGAG TGCTAGTCCT GACTTTGCTG GGCTTTCTAG 300 CTGCCGCCAC GTTCACTTGG AACCTGCTGG TGCTGGCCAC CATCCTCAGG GTACGCACCT 360 TCCACCGAGT ACCACACAAC CTGGTAGCAT CCATGGCTAT CTCGGATGTG CTAGTAGCTG 420 TGCTGGTTAT GCCTCTGAGC CTGGTACATG AACTGTCTGG GCGCCGCTGG CAGCTGGGCC 480 GGCGTCTATG CCAGCTGTGG ATTGCGTGTG ACGTCCTCTG CTGTACTGCC AGCATCTGGA 540 ATGTGACAGC AATAGCTTTG GACCGCTACT GGTCAATAAC GCGCCACCTG GAGTACACAC 600 TCCGTGCCCG CAAGCGTGTC TCCAACGTGA TGATCCTGCT CACTTGGGCA CTCTCCGCTG 660 TCATCTCTCT GGCTCCGCTG CTCTTTGGCT GGGGAGAGAC TTACTCGGAG CTCAGTGAAG 720 AATGCCAGGT CAGTCGCGAG CCTTCCTACA CCGTGTTCTC CACTGTGGGC GCCTTCTACC 780 TGCCGCTGTG TGTGGTGCTC TTTGTATACT GGAAGATTTA CAAGGCTGCG AAGTTCCGCA 840 TGGGCTCCAG GAAGACCAAC AGCGTCTCCC CCATACCTGA AGCTGTGGAG GTGAAGGACG 900 CTTCACAACA TCCCCAGATG GTGTTCACTG TCCGTCACGC CACCGTCACC TTCCAGACAG 960 AAGGGGACAC GTGGAGGGAA CAGAAGGAGC AAAGGGCAGC CCTCATGGTG GGCATCCTCA 1020 TTGGGGTGTT TGTCCTCTGC TGGTTCCCCT TCTTTGTTAC GGAGCTCATC AGTCCGCTGT 1080 GCTCCTGGGA TATCCCTGCC CTCTGGAAGA GCATCTTCCT GTGGCTGGGC TATTCCAACT 1140 CCTTCTTCAA CCCGCTCATC TACACGGCGT TCAACAGGAG CTACAGCAGT GCTTTTAAGG 1200 TCTTCTTCTC CAAGCAGCAG TGAGAGGCCA CATGGGAGTG CCTTCTTCCC GTAGCTTGTA 1260 GCTCGGTGGA CTGTCCTGCC TCACAAACCC CTGTAGTCTG CCCAGCTGTC CAGAGGAACA 1320 AGATCCATCT GCCAAGGGCA CCAGGGTCAC ATCAGAGCTC AGCTCACTTC AGTTCTGTGC 1380 CCGTGTGCTG GAAGGTGTCT CCTATAGGCT CTGGTAGCTT GTGTCCCCAG TCTGGGCACT 1440 CTTCCTCACA CTGTACCAGC AGCCACAGGC CTGGCCCACA ACGTGCCCAT TTCTCCTCCA 1500 ACTCCACTCC AGCGGGACCA TGAGAAGTTT GATCAGAACG AACAGGAGGA AGGAAGAGAG 1560 ACAATAAGGC AGGCAGAGAG AGGCAGAAAG AACAAGGCTG AAAGCCAGTG GGATCACATA 1620 CCTGGAACCC TCACACCAAG GAGACTTAGG CAGGTAGAAC AGGAATTTGG AGCCATCCTG 1680 GGCTACATAG TAAGTTCATA AATCAGTCTG AGCTGTCTGA CACAGACTTA GCAACAGCAA 1740 TGCACTAGAG AGGCTATTTG AAAAGCAGAG ACCATAAGGG CAAACTTCCC AGAACAGCCC 1800 TCACTTCACA GTTCTGCTCT GTGGTCCTGC AGTGTATGGC CCAATTCTGG GTCCTTCTGA 1860 ATATCTGATC ACAAGATTCT GTCCCCAAAC ATATCAAAGC ACCATCCCAT TTGTGATAAC 1920 AGTGATTCCT GTCTTTACCA TTTGTTCATT GTGAACCCAA AGTCTCCCTC TGTCTGTCTG 1980 TCTCTGTCTA TGCCTGTCTC CCCACCACCA CCACCTCTAG TTTCCAGTTA AAATCAACTC 2040 AGTCTATCAA CTGGAAAAGC AAAATATTTC CTTCCATTTT GAAACCACTC TTCATGAAAA 2100 ATCTATCAAT TTCACAGAAT CTGTCAAATT TATTTACTAT GGGTTTTTAC TGGTA 2155 (2) INFORMATION FOR SEQ ID N0:4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 357 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID N0:4: Met Asp Leu Pro He Asn Leu Thr Ser Phe Ser Leu Ser Thr Pro Ser 1 5 10 15 Thr Leu Glu Pro Asn Arg Ser Leu Asp Thr Glu Ala Leu Arg Thr Ser 20 25 30 Gin Ser Phe Leu Ser Ala Phe Arg Val Leu Val Leu Thr Leu Leu Gly 35 40 45 Phe Leu Ala Ala Ala Thr Phe Thr Trp Asn Leu Leu Val Leu Ala Thr 50 55 60 He Leu Arg Val Arg Thr Phe His Arg Val Pro His Asn Leu Val Ala 65 70 75 80 Ser Met Ala He Ser Asp Val Leu Val Ala Val Leu Val Met Pro Leu 85 90 95 Ser Leu Val His Glu Leu Ser Gly Arg Arg Trp Gin Leu Gly Arg Arg 100 105 110 Leu Cys Gin Leu Trp He Ala Cys Asp Val Leu Cys Cys Thr Ala Ser 115 120 125 He Trp Asn Val Thr Ala He Ala Leu Asp Arg Tyr Trp Ser He Thr 130 135 140 Arg His Leu Glu Tyr Thr Leu Arg Ala Arg Lys Arg Val Ser Asn Val 145 150 155 160 Met He Leu Leu Thr Trp Ala Leu Ser Ala Val He Ser Leu Ala Pro 165 170 175 Leu Leu Phe Gly Trp Gly Glu Thr Tyr Ser Glu Leu Ser Glu Glu Cys 180 185 190 Gin Val Ser Arg Glu Pro Ser Tyr Thr Val Phe Ser Thr Val Gly Ala 195 200 205 Phe Tyr Leu Pro Leu Cys Val Val Leu Phe Val Tyr Trp Lys He Tyr 210 215 220 Lys Ala Ala Lys Phe Arg Met Gly Ser Arg Lys Thr Asn Ser Val Ser 225 230 235 240 Pro He Pro Glu Ala Val Glu Val Lys Asp Ala Ser Gin His Pro Gin 245 250 255 Met Val Phe Thr Val Arg His Ala Thr Val Thr Phe Gin Thr Glu Gly 260 265 270 Asp Thr Trp Arg Glu Gin Lys Glu Gin Arg Ala Ala Leu Met Val Gly 275 280 285 He Leu He Gly Val Phe Val Leu Cys Trp Phe Pro Phe Phe Val Thr 290 295 300 Glu Leu He Ser Pro Leu Cys Ser Trp Asp He Pro Ala Leu Trp Lys 305 310 315 320 Ser He Phe Leu Trp Leu Gly Tyr Ser Asn Ser Phe Phe Asn Pro Leu 325 330 335 He Tyr Thr Ala Phe Asn Arg Ser Tyr Ser Ser Ala Phe Lys Val Phe 340 345 350 Phe Ser Lys Gin Gin 355 (2) INFORMATION FOR SEQ ID NO:5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1496 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5: AAAAACATGC ACATATTTTT TTAAAATGTT CTAAAAATAG AAGAGAACAA TACTTGAAAC 60 CTTCTCTGAA CTATGTTTCC CCCTCCTTTG TTACAGGTAT TCATTTCTTC AACTATGTAA 120 ACCTTTTAAA CAAAAAAATG GATTTTCTAA ACTCATCAGA CCAAAATTTA ACCTCAGAGG 180 AACTGTTAAA CCGAATGCCA TCCAAAATTC TGGTATCCCT CACTCTGTCT GGCCTGGCCT 240 TGATGACAAC CACCATCAAC TGCCTCGTGA TCACTGCAAT CATTGTGACT CGGAAGCTGC 300 ACCACCCAGC CAACTATTTA ATCTGTTCCT TGGCAGTTAC AGACTTTCTT GTTGCTGTCC 360 TGGTTATGCC CTTTAGCATC GTGTACATTG TGAGAGAGAG TTGGATTATG GGACAAGGAC 420 TCTGTGACCT TTGGCTGAGT GTTGACATCA TCTGCTGTAC CTGCTCCATC TTGCACCTGT 480 CGGCTATAGC GTTGGATAGG TACCGAGCAA TCACAGACGC AGTCGAGTAT GCCAGGAAGA 540 GGACTCCCAG GCATGCTGGC ATCACGATTA CAACAGTGTG GGTTATATCT GTGTTCATCT 600 CCGTGCCTCC TCTCTTCTGG AGGCACCAAG GAAATAGCCG TGATGATCAG TGTATCATCA 660 AACATGACCA TATTGTTTCC ACAATTTACT CCACGTTTGG AGCCTTCTAC ATCCCACTTG 720 TGTTGATATT GATCCTCTAC TACAAAATAT ACAGAGCAGC AAGGACACTA TACCACAAGA 780 GACAAGCAAG TCGGATGATA AAGGAGGAAC TGAATGGCCA AGTCCTTTTG GAGAGTGGTG 840 AGAAGAGCAT TAAACTGGTC TCCACATCCT ACATGTTAGA AAAATCCTTA TCTGATCCAT 900 CAACAGACTT TGATAGAATT CACAGCACAG TGAAAAGTCC CAGATCTGAG CTGAAGCACG 960 AGAAATCTTG GAGAAGACAG AAAATCTCAG GCACTCGAGA ACGCAAAGCA GCCACTACCC 1020 TGGGATTGAT CTTGGGCGCA TTTGTAATAT GTTGGTTGCC CTTTTTTGTA AAGGAATTGG 1080 TTGTTAATAT CTGTGAAAAA TGTAAAATTT CTGAAGAAAT GTCAAATTTT TTGGCATGGC 1140 TTGGTTACCT GAATTCTCTT ATAAACCCAC TGATTTATAC CATCTTTAAT GAAGACTTTA 1200 AGAAAGCCTT CCAAAAACTT GTACGATGTC GAAATTAGGA TTTAAAAAAA AGCCTATTTT 1260 TAAAGGGTAG AGGCTGTATT TCTTGGGGGG GGAGGGATAA CTAAATGAAT GTAAAGTAAT 1320 AAAAGATTGA AATTTTTAGA GAAAATATAT AAAGACTGCT AAAATTATAA GAGGATAAAT 1380 TTATTTTTAA TAGTACCAAG AAAATAAGAT ATCCTAATTT GGCCATCATT TTAATGTTCT 1440 CAAAATTAGG AAATAATTTA GGCAGCTCAG CTCATAATAT TTTTTCTATG CAATAT 1496 (2) INFORMATION FOR SEQ ID NO:6: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 47 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6: TAGGTGAAGT GAGGATGAAA ACCAACAGTT GAATGTGCCA CACCACG 47 (2) INFORMATION FOR SEQ ID NO:7: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 366 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7: Met Asp Phe Leu Asn Ser Ser Asp Gin Asn Leu Thr Ser Glu Glu Leu 1 5 10 15 Leu Asn Arg Met Pro Ser Lys He Leu Val Ser Leu Thr Leu Ser Gly 20 25 30 Leu Ala Leu Met Thr Thr Thr He Asn Cys Leu Val He Thr Ala He 35 40 45 He Val Thr Arg Lys Leu His His Pro Ala Asn Tyr Leu He Cys Ser 50 55 60 Leu Ala Val Thr Asp Phe Leu Val Ala Val Leu Val Met Pro Phe Ser 65 70 75 80 He Val Tyr He Val Arg Glu Ser Trp He Met Gly Gin Gly Leu Cys 85 90 95 Asp Leu Trp Leu Ser Val Asp He He Cys Cys Thr Cys Ser He Leu 100 105 110 His Leu Ser Ala He Ala Leu Asp Arg Tyr Arg Ala He Thr Asp Ala 115 120 125 Val Glu Tyr Ala Arg Lys Arg Thr Pro Arg His Ala Gly He Thr He 130 135 140 Thr Thr Val Trp Val He Ser Val Phe He Ser Val Pro Pro Leu Phe 145 150 155 160 Trp Arg His Gin Gly Asn Ser Arg Asp Asp Gin Cys He He Lys His 165 170 175 Asp His He Val Ser Thr He Tyr Ser Thr Phe Gly Ala Phe Tyr He 180 185 190 Pro Leu Val Leu He Leu He Leu Tyr Tyr Lys He Tyr Arg Ala Ala 195 200 205 Arg Thr Leu Tyr His Lys Arg Gin Ala Ser Arg Met He Lys Glu Glu 210 215 220 Leu Asn Gly Gin Val Leu Leu Glu Ser Gly Glu Lys Ser He Lys Leu 225 230 235 240 Val Ser Thr Ser Tyr Met Leu Glu Lys Ser Leu Ser Asp Pro Ser Thr 245 250 255 Asp Phe Asp Arg He His Ser Thr Val Lys Ser Pro Arg Ser Glu Leu 260 265 270 Lys His Glu Lys Ser Trp Arg Arg Gin Lys He Ser Gly Thr Arg Glu 275 280 285 Arg Lys Ala Ala Thr Thr Leu Gly Leu He Leu Gly Ala Phe Val He 290 295 300 Cys Trp Leu Pro Phe Phe Val Lys Glu Leu Val Val Asn He Cys Glu 305 310 315 320 Lys Cys Lys He Ser Glu Glu Met Ser Asn Phe Leu Ala Trp Leu Gly 325 330 335 Tyr Leu Asn Ser Leu He Asn Pro Leu He Tyr Thr He Phe Asn Glu 340 345 350 Asp Phe Lys Lys Ala Phe Gin Lys Leu Val Arg Cys Arg Asn 355 360 365 (2) INFORMATION FOR SEQ ID NO:8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1554 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8: ACTGTTCTCA TTAAATTTCT TAAATAAAAA GGAAAACTAA AACCTTCAAT CTGAACCTCA 60 TTTTTTTAAT CTATAGAATA TTCTGGGTAA ACATAACATA CACTTTTTAA AAATTATTCT 120 GAAAGGAAGA GAAAAGTTCT TGAAGCCTTC TCTGAACTGT TTTTTCTCTT CCCTTGTTAC 180 AGGTATCCAT TTTTCAGCTA TATTAATCTT TTAAAACAAA GAAAATGGAT TTCTTAAATT 240 CATCTGATCA AAACTTGACC TCAGAGGAAC TGTTAAACAG AATGCCATCC AAAATTCTGG 300 TGTCCCTCAC TCTGTCTGGG CTGGCACTGA TGACAACAAC TATCAACTCC CTTGTGATCG 360 CTGCAATTAT TGTGACCCGG AAGCTGCACC ATCCAGCCAA TTATTTAATT TGTTCCCTTG 420 CAGTCACAGA TTTTCTTGTG GCTGTCCTGG TGATGCCCTT CAGCATTGTG TATATTGTGA 480 GAGAGAGCTG GATTATGGGG CAAGTGGTCT GTGACATTTG GCTGAGTGTT GACATTACCT 540 GCTGCACGTG CTCCATCTTG CATCTCTCAG CTATAGCTTT GGATCGGTAT CGAGCAATCA 600 CAGATGCTGT TGAGTATGCC AGGAAAAGGA CTCCAAAGCA TGCTGGCATT ATGATTACAA 660 TAGTTTGGAT TATATCTGTT TTTATCTCTA TGCCTCCTCT ATTCTGGAGG CACCAAGGAA 720 CTAGCAGAGA TGATGAATGC ATCATCAAGC ACGACCACAT TGTTTCCACC ATTTACTCAA 780 CATTTGGAGC TTTCTACATC CCACTGGCAT TGATTTTGAT CCTTTACTAC AAAATATATA 840 GAGCAGCAAA GACATTATAC CACAAGAGAC AAGCAAGTAG GATTGCAAAG GAGGAGGTGA 900 ATGGCCAAGT CCTTTTGGAG AGTGGTGAGA AAAGCACTAA ATCAGTTTCC ACATCCTATG 960 TACTAGAAAA GTCTTTATCT GACCCATCAA CAGACTTTGA TAAAATTCAT AGCACAGTGA 1020 GAAGTCTCAG GTCTGAATTC AAGCATGAGA AATCTTGGAG AAGGCAAAAG ATCTCAGGTA 1080 CAAGAGAACG GAAAGCAGCC ACTACCCTGG GATTAATCTT GGGTGCATTT GTAATATGTT 1140 GGCTTCCTTT TTTTGTAAAA GAATTAGTTG TTAATGTCTG TGACAAATGT AAAATTTCTG 1200 AAGAAATGTC CAATTTTTTG GCATGGCTTG GGTATCTCAA TTCCCTTATA AATCCACTGA 1260 TTTACACAAT CTTTAATGAA GACTTCAAGA AAGCATTCCA AAAGCTTGTG CGATGTCGAT 1320 GTTAGTTTTA AAAATGTTTA TTATTGAAGG ATGGGGGTTT TTGAGGGGAG GAATAACTAG 1380 ATGAATGCCA AATAATAAAA CACTTAAGCT TTTAGAGGGA AATACATGAA AACTGCTAAA 1440 TTGATAAGGC TATAATTTAT ATTTTAATAG CAATGTGAAT ATAAAAGTTA TTGATCACCA 1500 CTATTCTAGG GTATTCAAAA TTAGAAAATA ATTTATGTAG GTTATAACAT ATTT 1554 (2) INFORMATION FOR SEQ ID NO:9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 366 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9: Met Asp Phe Leu Asn Ser Ser Asp Gin Asn Leu Thr Ser Glu Glu Leu 1 5 10 15 Leu Asn Arg Met Pro Ser Lys He Leu Val Ser Leu Thr Leu Ser Gly 20 25 30 Leu Ala Leu Met Thr Thr Thr He Asn Ser Leu Val He Ala Ala He 35 40 45 He Val Thr Arg Lys Leu His His Pro Ala Asn Tyr Leu He Cys Ser 50 55 60 Leu Ala Val Thr Asp Phe Leu Val Ala Val Leu Val Met Pro Phe Ser 65 70 75 80 He Val Tyr He Val Arg Glu Ser Trp He Met Gly Gin Val Val Cys 85 90 95 Asp He Trp Leu Ser Val Asp He Thr Cys Cys Thr Cys Ser He Leu 100 105 110 His Leu Ser Ala He Ala Leu Asp Arg Tyr Arg Ala He Thr Asp Ala 115 120 125 Val Glu Tyr Ala Arg Lys Arg Thr Pro Lys His Ala Gly He Met He 130 135 140 Thr He Val Trp He He Ser Val Phe He Ser Met Pro Pro Leu Phe 145 150 155 160 Trp Arg His Gin Gly Thr Ser Arg Asp Asp Glu Cys He He Lys His 165 170 175 Asp His He Val Ser Thr He Tyr Ser Thr Phe Gly Ala Phe Tyr He 180 185 190 Pro Leu Ala Leu He Leu He Leu Tyr Tyr Lys He Tyr Arg Ala Ala 195 200 205 Lys Thr Leu Tyr His Lys Arg Gin Ala Ser Arg He Ala Lys Glu Glu 210 215 220 Val Asn Gly Gin Val Leu Leu Glu Ser Gly Glu Lys Ser Thr Lys Ser 225 230 235 240 Val Ser Thr Ser Tyr Val Leu Glu Lys Ser Leu Ser Asp Pro Ser Thr 245 250 255 Asp Phe Asp Lys He His Ser Thr Val Arg Ser Leu Arg Ser Glu Phe 260 265 270 Lys His Glu Lys Ser Trp Arg Arg Gin Lys He Ser Gly Thr Arg Glu 275 280 285 Arg Lys Ala Ala Thr Thr Leu Gly Leu He Leu Gly Ala Phe Val He 290 295 300 Cys Trp Leu Pro Phe Phe Val Lys Glu Leu Val Val Asn Val Cys Asp 305 310 315 320 Lys Cys Lys He Ser Glu Glu Met Ser Asn Phe Leu Ala Trp Leu Gly 325 330 335 Tyr Leu Asn Ser Leu He Asn Pro Leu He Tyr Thr He Phe Asn Glu 340 345 350 Asp Phe Lys Lys Ala Phe Gin Lys Leu Val Arg Cys Arg Cys 355 360 365 (2) INFORMATION FOR SEQ ID NO:10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 2040 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10: CTTTATTTTT TATTTAATTA TTTTTACTTA GGGCTTAAAA AATATCCACC AAAGAGGTTC 60 TTCACCAGTT CATCCCTGAC CCCGAGTCTT CTTGAAAAGC AAACGGCTCC CACCCGCTTG 120 TCATTTGCTA CAGTGTAGAG GCCAGGGGGT CTGCGGCAGG GCGAGCCCGG GCTGAGCTTT 180 CGCACGGTGC GCATCAGCCG GGCTGCCCAG CAGGGGAAGC CCGTCCCGGT GCGCGCCCGG 240 CGCTGGCGGC TGCCGGAGGC GGTGGCTGGG ACGCGGCGCG GCTGCCGCAG GGGAGCGGCG 300 GCGGCGGGCG CGAGGGGCGG GGCGCACTCC GCAACTTCGG CCGCGGCGGC CCGGCGCTCC 360 CGGCCCCGGC GCGCATCGCT GCGGGGCTGC GGTGCGGCCA ACCCGGCCAG GCTCGGCTCG 420 CCACCCTGCT CCTCTCGCGT GCCCGTCGGG GACCGCTGGT GCCTCCCGCG GGGAGTCCTC 480 GCCCACGCGT CATCCGCAGA GGCTGGGGGA CCCTGGGACG TGCGGGGTCG CGAGGCCGAG 540 CCGGGCGCCC CCCAGTGGCC AGCCCCGGAC CCCATGGCTG GGCCGCGCGG AGCCGAGCGG 600 GCAAGGTGAA TCCAGCCCCG GGGCCGGCTG CCGGAGCGCT TGGCGGGGTC GCCGGCTCCA 660 TGGGCAGCGG CGCTCGGCAC GATGATGGAC GTTAACAGCA GCGGCCGCCC CGACCTCTAC 720 GGCCATCTCC GTTCACTCAT CCTGCCGGAG GTGGGGCGCG GGCTGCAGGA CCTGAGCCCC 780 GACGGTGGCG CCCACCCTGT GGTGAGCTCC TGGATGCCGC ACCTGCTGAG TGGCTTCCTA 840 GAGGTGACGG CTAGCCCGGC GCCCACCTGG GACGCGCCAC CGGACAATGT CTCAGGCTGC 900 GGGGAGCAGA TCAACTATGG CAGAGTGGAG AAAGTTGTGA TCGGCTCCAT CCTGACGCTC 960 ATCACGCTGC TGACGATCGC AGGCAACTGC CTGGTGGTGA TCTCGGTGTG CTTCGTCAAG 1020 AAGCTCCGCC AGCCCTCCAA CTACCTGATT GTGTCCCTGG CGCTGGCTGA CCTCTCGGTG 1080 GCCGTGGCGG TCATGCCTTT CGTTAGTGTC ACCGACCTCA TCGGGGGCAA GTGGATCTTC 1140 GGCCACTTCT TCTGCAACGT CTTCATCGCC ATGGACGTCA TGTGCTGCAC GGCCTCGATC 1200 ATGACCCTGT GCGTGATCAG CATCGACAGG TACCTTGGGA TCACGAGACC CCTCACGTAC 1260 CCGGTGAGGC AAAATGGGAA ATGTATGGCC AAAATGATTC TGTCGGTCTG GCTGCTCTCT 1320 GCCTCCATCA CCTTACCTCC TCTCTTCGGA TGGGCTCAGA ATGTGAACGA TGACAAAGTG 1380 TGCTTGATCA GCCAGGATTT TGGCTACACG ATCTACTCCA CTGCGGTGGC GTTTTATATC 1440 CCCATGTCGG TCATGCTGTT CATGTACTAT CAGATTTACA AGGCCGCCAG GAAGAGTGCA 1500 GCCAAACACA AGTTCCCAGG CTTCCCACGC GTGCAGCCGG AGAGTGTCAT CTCCCTGAAT 1560 GGTGTGGTGA AGCTCCAGAA GGAGGTGGAA GAGTGTGCGA ACCTTTCGAG ACTGCTCAAA 1620 CACGAAAGGA AAAACATCTC CATCTTCAAG CGGGAACAGA AAGCAGCCAC TACCTTGGGG 1680 ATCATCGTGG GAGCCTTCAC TGTGTGCTGG CTGCCGTTTT TCCTCTTGTC CACAGCCCGC 1740 CCCTTTATCT GTGGCACCTC CTGTAGCTGC ATTCCTCTGT GGGTGGAGAG GACATGTCTG 1800 TGGCTGGGCT ATGCAAACTC TCTCATTAAT CCTTTTATAT ATGCCTTCTT CAACCGGGAC 1860 CTGAGGACCA CCTATCGTAG CCTACTCCAG TGCCAGTACC GGAATATCAA CCGGAAGCTC 1920 TCTGCTGCAG GCATGCATGA AGCCCTGAAA CTTGCTGAGA GGCCCGAGAG ATCCGAGTTT 1980 GTGCTGTAAG ACAAAACTCT GACCACTGTG GGAAAAAGGG TCATGATACA TGATCCAGAG 2040 (2) INFORMATION FOR SEQ ID NO:11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 435 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11: Met Met Asp Val Asn Ser Ser Gly Arg Pro Asp Leu Tyr Gly His Leu 1 5 10 15 Arg Ser Leu He Leu Pro Glu Val Gly Arg Gly Leu Gin Asp Leu Ser 20 25 30 Pro Asp Gly Gly Ala His Pro Val Val Ser Ser Trp Met Pro His Leu 35 40 45 Leu Ser Gly Phe Leu Glu Val Thr Ala Ser Pro Ala Pro Thr Trp Asp 50 55 60 Ala Pro Pro Asp Asn Val Ser Gly Cys Gly Glu Gin He Asn Tyr Gly 65 70 75 80 Arg Val Glu Lys Val Val He Gly Ser He Leu Thr Leu He Thr Leu 85 90 95 Leu Thr He Ala Gly Asn Cys Leu Val Val He Ser Val Cys Phe Val 100 105 110 Lys Lys Leu Arg Gin Pro Ser Asn Tyr Leu He Val Ser Leu Ala Leu 115 120 125 Ala Asp Leu Ser Val Ala Val Ala Val Met Pro Phe Val Ser Val Thr 130 135 140 Asp Leu He Gly Gly Lys Trp He Phe Gly His Phe Phe Cys Asn Val 145 150 155 160 Phe He Ala Met Asp Val Met Cys Cys Thr Ala Ser He Met Thr Leu 165 170 175 Cys Val He Ser He Asp Arg Tyr Leu Gly He Thr Arg Pro Leu Thr 180 185 190 Tyr Pro Val Arg Gin Asn Gly Lys Cys Met Ala Lys Met He Leu Ser 195 200 205 Val Trp Leu Leu Ser Ala Ser He Thr Leu Pro Pro Leu Phe Gly Trp 210 215 220 Ala Gin Asn Val Asn Asp Asp Lys Val Cys Leu He Ser Gin Asp Phe 225 230 235 240 Gly Tyr Thr He Tyr Ser Thr Ala Val Ala Phe Tyr He Pro Met Ser 245 250 255 Val Met Leu Phe Met Tyr Tyr Gin He Tyr Lys Ala Ala Arg Lys Ser 260 265 270 Ala Ala Lys His Lys Phe Pro Gly Phe Pro Arg Val Gin Pro Glu Ser 275 280 285 Val He Ser Leu Asn Gly Val Val Lys Leu Gin Lys Glu Val Glu Glu 290 295 300 Cys Ala Asn Leu Ser Arg Leu Leu Lys His Glu Arg Lys Asn He Ser 305 310 315 320 He Phe Lys Arg Glu Gin Lys Ala Ala Thr Thr Leu Gly He He Val 325 330 335 Gly Ala Phe Thr Val Cys Trp Leu Pro Phe Phe Leu Leu Ser Thr Ala 340 345 350 Arg Pro Phe He Cys Gly Thr Ser Cys Ser Cys He Pro Leu Trp Val 355 360 365 Glu Arg Thr Cys Leu Trp Leu Gly Tyr Ala Asn Ser Leu He Asn Pro 370 375 380 Phe He Tyr Ala Phe Phe Asn Arg Asp Leu Arg Thr Thr Tyr Arg Ser 385 390 395 400 Leu Leu Gin Cys Gin Tyr Arg Asn He Asn Arg Lys Leu Ser Ala Ala 405 410 415 Gly Met His Glu Ala Leu Lys Leu Ala Glu Arg Pro Glu Arg Ser Glu 420 425 430 Phe Val Leu 435 (2) INFORMATION FOR SEQ ID NO:12: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (A) NAME/KEY: Modified-site (B) LOCATION: 4 (D) OTHER INFORMATION: /note- "Xaa is either Ala or Ser" (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12: Cys Ala He Xaa Leu Asp Arg Tyr 1 5 (2) INFORMATION FOR SEQ ID NO:13: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 7 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (A) NAME/KEY: Modified-site (B) LOCATION: 1 (D) OTHER INFORMATION: /note- "Xaa is either Cys or Met" (ix) FEATURE: (A) NAME/KEY: Modified-site (B) LOCATION: 3 (D) OTHER INFORMATION: /note- "Xaa is either Leu or Cys" (xi) SEQUENCE DESCRIPTION: SEQ ID NO:13: Xaa Trp Xaa Pro Phe Phe He 1 5 (2) INFORMATION FOR SEQ ID NO:14: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (A) NAME/KEY: Modified-site (B) LOCATION: 2 (D) OTHER INFORMATION: /note- "Xaa is either Val or Gly" (ix) FEATURE: (A) NAME/KEY: Modified-site (B) LOCATION: 5 (D) OTHER INFORMATION: /note- "Xaa is either Phe or Tyr" (xi) SEQUENCE DESCRIPTION: SEQ ID NO:14: Phe Xaa Ala Phe Xaa He Pro Leu 1 5 (2) INFORMATION FOR SEQ ID NO:15: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 40 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:15: AGCTCCGCGG AGCTCTATGY GCNATHGCNY TNGAYMGNTA 40 (2) INFORMATION FOR SEQ ID NO:16: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 40 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:16: AGCTCCGCGG AGCTCTATGY GCNATHWSNY TNGAYMGNTA 40 (2) INFORMATION FOR SEQ ID NO:17: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 36 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:17: AGCTCCGCGG AGCTCDATRA ARAANGGNAR CCARCA 36 (2) INFORMATION FOR SEQ ID NO:18: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 36 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:18: AGCTCCGCGG AGCTCDATRA ARAANGGRCA CCACAT 36 (2) INFORMATION FOR SEQ ID NO:19: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 36 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:19: ACGTGCGGCC GCNARNGGDA TRWARAANGC NMCRAA 36 (2) INFORMATION FOR SEQ ID NO:20: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:20: TCGGACCCCG ACGCGTGCAC CATC 24 (2) INFORMATION FOR SEQ ID NO:21: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:21: GTGAATAACA CCACGTGCGT GCTC 24 (2) INFORMATION FOR SEQ ID NO:22: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:22: AAGGAGGGGA GCTGCCTGCT TGCC 24 (2) INFORMATION FOR SEQ ID NO:23: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:23: GGATCCCATG CTTCTGCCGG 20 (2) INFORMATION FOR SEQ ID NO:24: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 41 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:24: GCACCGCGGA GCTCAAGCTT CCCCCCCCCC CCCCCCCCCC C 41 (2) INFORMATION FOR SEQ ID NO:25: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 25 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25: TGCCCAAGTG AGCAGGATCA TCACG 25 (2) INFORMATION FOR SEQ ID NO:26: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 25 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:26: TGGCGCGTTA TTGACCAGTA GCGGT 25 (2) INFORMATION FOR SEQ ID NO:27: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:27: GGCTGGGTGG TGCAGCTTCC G 21 (2) INFORMATION FOR SEQ ID NO:28: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 43 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:28: CAGCTACGGC GGCCGCAAGC TTAAAATGGA TTTTCTAAAC TCA 43 (2) INFORMATION FOR SEQ ID NO:29: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 26 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO ( iv) ANTI - SENSE : NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:29: CTGTTGTAAT CGTGATGCCA GCATGC 26 (2) INFORMATION FOR SEQ ID NO:30: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (A) NAME/KEY : Modified- site (B) LOCATION : 2 (D) OTHER INFORMATION: /note- "Xaa is either Leu or He" (ix) FEATURE: (A) NAME/KEY : Modified- site (B) LOCATION : 5 (D) OTHER INFORMATION: /note- "Xaa is either Leu or Ser" (ix) FEATURE: (A) NAME/KEY: Modified-site (B) LOCATION: 8 (D) OTHER INFORMATION: /note- "Xaa is either Leu or Phe" (xi) SEQUENCE DESCRIPTION: SEQ ID NO:30: Trp Xaa Gly Tyr Xaa Asn Ser Xaa 1 5 (2) INFORMATION FOR SEQ ID NO:31: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 35 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:31: GCTCATCTAG ANARNSWRTT NVDRTANCCN ADCCA 35 (2) INFORMATION FOR SEQ ID NO:32: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 8 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:32: Phe Val Tyr Trp Lys He Tyr Lys 1 5 (2) INFORMATION FOR SEQ ID NO:33: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 40 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:33: CTGGTGGTCG ACGGTACCTT YGTNTAYTGG AARATHAYAA 40 (2) INFORMATION FOR SEQ ID NO:34: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:34: CCTCAGGAGT CTGAGACGGT ATTC 24 (2) INFORMATION FOR SEQ ID NO:35: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 24 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:35: GCTGTGGAGG TGAAGGACGT TCAC 24 (2) INFORMATION FOR SEQ ID NO:36: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 17 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:36: Met He Lys Glu Glu Leu Asn Gly Gin Val Leu Leu Glu Ser Gly Glu 1 5 10 15 Lys (2) INFORMATION FOR SEQ ID NO:37: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:37: His Ser Thr Val Lys Ser Pro Arg Ser Glu Leu Lys His Glu Lys Ser 1 5 10 15 Trp Arg (2) INFORMATION FOR SEQ ID NO:38: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 16 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:38: Trp Thr He Thr Arg His Leu Gin Tyr Thr Leu Arg Thr Arg Arg Arg 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:39: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:39: Val Val Pro Leu Pro Ala Thr Thr Gin Ala Lys Glu Ala Pro Gin Glu 1 5 10 15 Ser Glu Thr Val 20 (2) INFORMATION FOR SEQ ID NO:40: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:40: Arg Ala Thr Val Ala Phe Gin Thr Ser Gly Asp Ser Trp Arg Glu Gin 1 5 10 15 Lys Glu Lys Arg 20 (2) INFORMATION FOR SEQ ID NO:41: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:41: Lys Asn Tyr Asn Asn Ala Phe Lys Ser Leu Phe Thr Lys Gin Arg 1 5 10 15 (2) INFORMATION FOR SEQ ID NO: 2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 19 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:42: Val Ser Pro He Pro Glu Ala Val Glu Val Lys Asp Ala Ser Gin His 1 5 10 15 Pro Gin Met (2) INFORMATION FOR SEQ ID NO:43: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:43: Arg Ser Tyr Ser Ser Ala Phe Lys Val Phe Phe Ser Lys Gin Gin 1 5 10 15 (2) INFORMATION FOR SEQ ID NO: 4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 19 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:44: Arg Lys Ser Ala Ala Lys His Lys Phe Pro Gly Phe Pro Arg Val Gin 1 5 10 15 Pro Glu Ser (2) INFORMATION FOR SEQ ID NO:45: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:45: Pro Glu Val Gly Arg Gly Leu Gin Asp Leu Ser Pro Asp Gly Gly Ala 1 5 10 15 His Pro Val Val Ser 20 (2) INFORMATION FOR SEQ ID NO: 6: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 19 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:46: Ser Arg Leu Leu Lys His Glu Arg Lys Asn He Ser He Phe Lys Arg 1 5 10 15 Glu Gin Lys (2) INFORMATION FOR SEQ ID NO:47: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 52 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:47: Met Glu Val Cys Asn Leu Ser Gly Ala Thr Pro Gly He Ala Phe Pro 1 5 10 15 Pro Gly Pro Glu Ser Cys Ser Asp Ser Pro Ser Ser Gly Arg Ser Met 20 25 . 30 Gly Ser Thr Pro Gly Gly Leu He Leu Ser Gly Arg Glu Pro Pro Phe 35 40 45 Ser Ala Phe Thr 50 (2) INFORMATION FOR SEQ ID NO: 8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 28 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:48: Pro Leu Ser Leu Val Ser Glu Leu Ser Ala Gly Arg Arg Trp Gin Leu 1 5 10 15 Gly Arg Ser Leu Cys His Val Trp He Ser Phe Asp 20 25 (2) INFORMATION FOR SEQ ID NO: 9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 33 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 9: Ala Pro Leu Leu Phe Gly Trp Gly Glu Ala Tyr Asp Ala Arg Leu Gin 1 5 10 15 Arg Cys Gin Val Ser Gin Glu Pro Ser Tyr Ala Val Phe Ser Thr Cys 20 25 30 Gly (2) INFORMATION FOR SEQ ID NO:50: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 30 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:50: Trp He Pro Phe Phe Leu Thr Glu Leu Val Ser Pro Leu Cys Ala Cys 1 5 10 15 Ser Leu Pro Pro He Trp Lys Ser He Phe Leu Trp Leu Gly 20 25 30 (2) INFORMATION FOR SEQ ID NO:51: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 15 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:51: Lys Asn Tyr Asn Asn Ala Phe Lys Ser Leu Phe Thr Lys Gin Arg 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:52: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 40 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:52: Met Asp Leu Pro He Asn Leu Thr Ser Phe Ser Leu Ser Thr Pro Ser 1 5 10 15 Thr Leu Glu Pro Asn Arg Ser Leu Asp Thr Glu Ala Leu Arg Thr Ser 20 25 30 Gin Ser Phe Leu Ser Ala Phe Arg 35 40 (2) INFORMATION FOR SEQ ID NO:53: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 26 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION : SEQ ID NO: 53 : Pro Leu Ser Leu Val His Glu Leu Ser Gly Arg Arg Trp Gin Leu Gly 1 5 10 15 Arg Arg Leu Cys Gin Leu Trp He Ala Leu 20 25 (2) INFORMATION FOR SEQ ID NO:54: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 33 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:54: Ala Pro Leu Leu Phe Gly Trp Gly Glu Thr Tyr Ser Glu Leu Ser Glu 1 5 10 15 Glu Cys Gin Val Ser Arg Glu Pro Ser Tyr Thr Val Phe Ser Thr Val 20 25 30 Gly (2) INFORMATION FOR SEQ ID NO:55: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 23 amino acids (B) TYPE: amino acid (D TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:55: Val Thr Glu Leu He Ser Pro Leu Cys Ser Trp Asp He Pro Ala Leu 1 5 10 15 Trp Lys Ser He Phe Leu Trp 20 (2) INFORMATION FOR SEQ ID NO:56: (i) SEQUENCE CHARACTERISTICS: 170 - (A) LENGTH: 15 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:56: Arg Ser Tyr Ser Ser Ala Phe Lys Val Phe Phe Ser Lys Gin Gin 1 5 10 15 (2) INFORMATION FOR SEQ ID NO:57: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 23 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:57: Met Asp Phe Leu Asn Ser Ser Asp Gin Asn Leu Thr Ser Glu Glu Leu 1 5 10 15 Leu Asn Arg Met Pro Ser Lys 20 (2) INFORMATION FOR SEQ ID NO:58: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 27 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:58: Met Pro Phe Ser He Val Tyr He Val Arg Glu Ser Trp He Met Gly 1 5 10 15 Gin Gly Leu Cys Asp Leu Trp Leu Ser Val Asp 20 25 (2) INFORMATION FOR SEQ ID NO:59: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 36 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:59: Phe He Ser Met Pro Pro Leu Phe Trp Arg His Gin Gly Asn Ser Arg 1 5 10 15 Asp Asp Gin Cys He He Lys His Asp His He Val Ser Thr He Tyr 20 25 30 Ser Thr Phe Gly 35 (2) INFORMATION FOR SEQ ID NO:60: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 26 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:60: Trp Leu Pro Phe Phe Val Lys Glu Leu Val Val Asn He Cys Glu Lys 1 5 10 15 Cys Lys He Ser Glu Glu Met Ser Asn Phe 20 25 (2) INFORMATION FOR SEQ ID NO:61: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:61: Tyr Thr He Phe Asn Glu Asp Phe Lys Lys Ala Phe Gin Lys Leu Val 1 5 10 15 Arg Cys Arg Asn 20 (2) INFORMATION FOR SEQ ID NO:62: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 23 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:62: Met Asp Phe Leu Asn Ser Ser Asp Gin Asn Leu Thr Ser Glu Glu Leu 1 5 10 15 Leu Asn Arg Met Pro Ser Lys 20 (2) INFORMATION FOR SEQ ID NO:63: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 27 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:63: Met Pro Phe Ser He Val Tyr He Val Arg Glu Ser Trp He Met Gly 1 5 10 15 Gin Val Val Cys Asp He Trp Leu Ser Val Asp 20 25 (2) INFORMATION FOR SEQ ID NO:64: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 35 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION : SEQ ID NO : 64 : Phe He Ser Val Pro Pro Leu Phe Trp Arg His Gin Gly Thr Ser Asp 1 5 10 15 Asp Glu Cys He He Lys His Asp His He Val Ser Thr He Tyr Ser 20 25 30 Thr Phe Gly 35 (2) INFORMATION FOR SEQ ID NO:65: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 26 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:65: Trp Leu Pro Phe Phe Val Lys Glu Leu Val Val Asn Val Cys Asp Lys 1 5 10 15 Cys Lys He Ser Glu Glu Met Ser Asn Phe 20 25 (2) INFORMATION FOR SEQ ID NO:66: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:66: Tyr Thr He Phe Asn Glu Asp Phe Lys Lys Ala Phe Gin Lys Leu Val 1 5 10 15 Arg Cys Arg Cys 20 (2) INFORMATION FOR SEQ ID NO:67: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 84 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:67: Met Met Asp Val Asn Ser Ser Gly Arg Pro Asp Leu Tyr Gly His Leu 1 5 10 15 Arg Ser Leu He Leu Pro Glu Val Gly Arg Gly Leu Gin Asp Leu Ser 20 25 30 Pro Asp Gly Gly Ala His Pro Val Val Ser Ser Trp Met Pro His Leu 35 40 45 Leu Ser Gly Phe Leu Glu Val Thr Ala Ser Pro Ala Pro Thr Trp Asp 50 55 60 Ala Pro Pro Asp Asn Val Ser Gly Cys Gly Glu Gin He Asn Tyr Gly 65 70 75 80 Arg Val Glu Lys (2) INFORMATION FOR SEQ ID NO:68: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 31 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (A) NAME/KEY: Region (B) LOCATION: (7"8) (D) OTHER INFORMATION: /note- "An unspecified amino acid residue is present in this location" (xi) SEQUENCE DESCRIPTION: SEQ ID NO:68: Met Pro Phe Val Ser Val Thr Leu He Gly Gly Lys Trp He Phe Gly 1 5 10 15 His Phe Phe Cys Asn Val Phe He Ala Met Asp Val Met Cys Cys 20 25 30 (2) INFORMATION FOR SEQ ID NO:69: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 34 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (A) NAME/KEY: Region (B) LOCATION: (11 A 12) (D) OTHER INFORMATION: /note- "An unspecified amino acid residue is present in this location" (xi) SEQUENCE DESCRIPTION: SEQ ID NO:69: Thr Leu Pro Pro Leu Phe Gly Trp Ala Gin Asn Asn Asp Asp Lys Val 1 5 10 15 Cys Leu He Ser Gin Asp Phe Gly Val Thr He Tyr Ser Thr Ala Val 20 25 30 Ala Phe (2) INFORMATION FOR SEQ ID NO:70: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 36 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:70: Phe Thr Val Cys Trp Leu Pro Phe Phe Leu Leu Ser Thr Ala Arg Pro 1 5 10 15 Phe He Cys Gly Thr Ser Cys Ser Cys He Pro Leu Trp Val Glu Arg 20 25 30 Thr Cys Leu Trp 35 (2) INFORMATION FOR SEQ ID NO:71: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 47 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:71: Phe Phe Asn Arg Asp Leu Arg Thr Thr Tyr Arg Ser Leu Leu Gin Cys 1 5 10 15 Gin Tyr Arg Asn He Asn Arg Lys Leu Ser Ala Ala Gly Met His Glu 20 25 30 Ala Leu Lys Leu Ala Glu Arg Pro Glu Arg Ser Glu Phe Val Leu 35 40 45 (2) INFORMATION FOR SEQ ID NO:72: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:72: CAAGCAAGTA GGATTGCAAA G 21 (2) INFORMATION FOR SEQ ID NO:73: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: single (D) TOPOLOGY: linear (ii) MOLECULE TYPE: cDNA (iii) HYPOTHETICAL: NO (iv) ANTI-SENSE: NO (xi) SEQUENCE DESCRIPTION: SEQ ID NO:73: CACAAGCTTT TGGAATGCTT T 21

Claims: What Iε Claimed Iε: I. An iεolated protein that iε a εerotonin receptor εelected from the group conεiεting of 5-HT 1E . like ' 5 - T 5 ' 5 - HT 5B and ^" 2. The iεolated protein of claim 1 wherein said serotonin receptor is human. 3. The isolated protein of claim 1 wherein εaid εerotonin receptor iε the 5-HT 5α εerotonin receptor REC17. 4. The iεolated protein of claim 3 wherein εaid REC17 εerotonin receptor haε the amino acid residue sequence εhown in SEQ ID NO 4. 5. The iεolated protein of claim 1 wherein εaid εerotonin receptor iε the 5-HT 5β εerotonin receptor MR22. 6. The iεolated protein of claim 5 wherein εaid MR22 εerotonin receptor haε the amino acid reεidue εequence εhown in SEQ ID NO 2. 7. The iεolated protein of claim 1 wherein εaid εerotonin receptor iε the 5-HT 1E _ Uke εerotonin receptor MR77. 8. The iεolated protein of claim 7 wherein εaid MR77 εerotonin receptor haε the amino acid residue sequence shown in SEQ ID NO 7 or 9. 9. The isolated protein of claim 1 wherein εaid εerotonin receptor iε the 5-HT 6 εerotonin receptor REC20. 10. The iεolated protein of claim 9 wherein εaid REC20 εerotonin receptor haε the amino acid residue sequence εhown in SEQ ID NO 11. II. A DNA εegment encoding a serotonin receptor selected from the group consiεting of 5 ~HT 1E . Uke , 5- HT 5α , 5-HT 5β and 5-HT 6 . 12. The DNA εegment of claim 11 wherein εaid εerotonin receptor iε the 5-HT 5α εerotonin receptor REC17 and haε a coding εequence εubεtantially the εame aε the coding nucleotide εequence shown in SEQ ID NO 3. 13. The DNA segment of claim 11 wherein said serotonin receptor iε the 5-HT 5β εerotonin receptor MR22 and haε a coding sequence subεtantially the εame as the coding nucleotide sequence εhown in SEQ ID NO 1. 14. The DNA εegment of claim 11 wherein εaid εerotonin receptor is the 5-HT 1E _ Hke serotonin receptor MR77 and has a coding sequence substantially the same as the coding nucleotide sequence shown in SEQ ID NO 5 or 8. 15. The DNA segment of claim 11 wherein said serotonin receptor is the 5-HT 6 serotonin receptor REC20 and has a coding sequence εubεtantially the εame as the coding nucleotide sequence shown in SEQ ID NO 10. 16. A vector comprising the DNA segment of claim 11, wherein said vector is adapted for expreεεion of εaid serotonin receptor in a hoεt cell containing εaid vector. 17. The vector of claim 16 wherein εaid vector iε adapted for expreεsion of said serotonin receptor in a mammalian host cell. 18. An isolated mammalian cell comprising the DNA segment of claim 11. 19. The isolated mammalian cell of claim 18 wherein said DNA is present in a vector adapted for expression of said serotonin receptor in said mammalian cell. 20. The isolated mammalian cell of claim 19 that further comprises a cell surface εerotonin receptor expreεεed from εaid vector. 21. The iεolated mammalian cell of claim 20 wherein εaid cell εurface εerotonin receptor iε a receptor εelected from the group conεiεting of MR22, MR77, REC17 and REC20. 22. A method for determining whether a ligand can bind to a preεelected εerotonin receptor which compriεeε; (a) contacting a mammalian cell with a candidate ligand under conditionε permitting binding of a known serotonin receptor ligand to said εerotonin receptor, εaid mammalian cell compriεing a vector adapted for expreεεing a εerotonin receptor in εaid mammalian cell, εaid vector compriεing a DNA εegment encoding εaid preεelected serotonin receptor selected from the group conεisting of 5-HT 1E _ ljke , 5-HT 5β , 5-HT 5β and 5-HT 6 and said mammalian containing a cell surface serotonin receptor expressed from said vector; and (b) detecting the presence of any of εaid candidate ligand bound to εaid cell εurface εerotonin receptor, and thereby determining whether the ligand bindε to εaid receptor. 23. The method of claim 22 wherein εaid DNA εegment haε a nucleotide εequence that encodeε a REC17 serotonin receptor having the amino acid residue sequence εhown in SEQ ID NO 4. 24. The method of claim 22 wherein εaid DNA εegment haε a nucleotide εequence that encodeε a MR22 εerotonin receptor having the amino acid reεidue εequence εhown in SEQ ID NO 2. 25. The method of claim 22 wherein εaid DNA εegment haε a nucleotide εequence that encodeε a MR77 εerotonin receptor having the amino acid reεidue εequence εhown in SEQ ID NOε 7 or 9. 26. The method of claim 22 wherein εaid DNA εegment haε a nucleotide εequence that encodeε a REC20 serotonin receptor having the amino acid residue sequence shown in SEQ ID NO 11. 27. A method for screening drugs to identify a candidate drug that can activate a preselected εerotonin receptor which compriεes; (a) contacting a mammalian cell with said candidate drug under conditions permitting activation of εaid serotonin receptor by a known serotonin receptor activating drug, said mammalian cell comprising a vector adapted for expresεing a serotonin receptor in said mammalian cell, said vector comprising a DNA segment encoding said preεelected serotonin receptor selected from the group consiεting of 5-HT 1E _ like , 5-HT 5β , 5-HT 5β and 5-HT 6 and said mammalian containing a cell surface εerotonin receptor expressed from said vector; and (b) detecting the activation status of said cell surface serotonin receptor, and thereby determining whether the drug activates said receptor. 28. The method of claim 27 wherein said DNA segment has a nucleotide sequence that encodes a REC17 εerotonin receptor having the amino acid reεidue εequence εhown in SEQ ID NO 4. 29. The method of claim 27 wherein εaid DNA segment haε a nucleotide εequence that encodeε a MR22 εerotonin receptor having the amino acid reεidue εequence εhown in SEQ ID NO 2. 30. The method of claim 27 wherein εaid DNA εegment haε a nucleotide εequence that encodeε a MR77 serotonin receptor having the amino acid residue εequence εhown in SEQ ID NOε 7 or 9. 31. The method of claim 27 wherein εaid DNA segment has a nucleotide εequence that encodeε a REC20 εerotonin receptor having the amino acid residue sequence shown in SEQ ID NO 11. 32. An isolated nucleic acid molecule probe comprising a nucleic acid segment of at least 10 nucleotides in length having a εequence correεponding to or complementary to a εequence included within the coding region of a nucleotide εequence that encodeε a εerotonin receptor εelected from the group conεiεting of 5-HT 1E . ljke , 5-HT 5β , 5-HT 5β and 5-HT 6 . 33. A method for detecting the preεence of a εerotonin receptor gene in the nucleic acid of a cell compriεing: (a) contacting the nucleic acid of said cell under nucleic acid hybridization conditions permitting hybridization of complementary nucleotide sequences in a hybridization reaction admixture with an isolated nucleic acid molecule probe compriεing a nucleic acid εegment of at leaεt 10 nucleotideε in length having a sequence corresponding to or complementary to a sequence included within the coding region of a nucleotide εequence that encodeε a εerotonin receptor εelected from the group conεiεting of 5-HT 1E . h - ke , 5-HT 5a , 5-HT 5β and 5-HT 6 ; (b) maintaining said hybridization reaction admixture under hybridization conditions εufficient for said probe to hybridize with any nucleic acid complementary to said probe and form a probe- containing nucleic acid duplex; and (c) detecting the preεence of a probe- containing duplex in εaid admixture, and thereby detecting the preεence of a εerotonin receptor gene in the nucleic acid of said cell. 34. The method of claim 33 wherein said contacting is by in situ hybridization. 35. The method of claim 33 wherein said nucleic acid of said cell mesεenger RNA. 36. An oligonucleotide of about 10 to 100 nucleotideε in length having a sequence capable of hybridizing specifically with a structural protein region of the nucleotide sequence that encodes a serotonin receptor selected from the group consiεting of 5-HT 1E _ ljke , 5-HT 5α , 5-HT 5β and 5-HT 6 , and chemical analogε thereof. 37. A method of altering serotonin receptor gene expression in a cell comprising administering to a subject an amount of a pharmaceutical composition comprising a physiologically acceptable carrier and the oligonucleotide of claim 36 effective to enter said cell and reduce expression of said serotonin receptor gene. 38. The method of claim 37 wherein said serotonin receptor is REC17 and said oligonucleotide has a sequence complementary the nucleotide sequence shown in SEQ ID NO 3. 39. The method of claim 37 wherein said serotonin receptor is MR22 and said oligonucleotide has a sequence complementary the nucleotide sequence shown in SEQ ID NO 1. 40. The method of claim 37 wherein εaid εerotonin receptor iε MR77 and εaid oligonucleotide haε a εequence complementary the nucleotide εequence εhown in SEQ ID NO 8. 41. The method of claim 37 wherein said serotonin receptor is REC20 and εaid oligonucleotide haε a εequence complementary the nucleotide εequence εhown in SEQ ID NO 10. 42. A εerotonin receptor polypeptide having a length of no more than about 100 amino acid reεidueε and a εequence that substantially corresponds to a portion of the sequence of the REC17 serotonin receptor shown in SEQ ID NO 4, said polypeptide including an amino acid residue sequence repreεented by a formula εelected from the group conεisting of SEQ ID NOε 42, 43, 52, 53, 54, 55 and 56. 43. A εerotonin receptor polypeptide having a length of no more than about 100 amino acid reεidueε and a εequence that εubεtantially correεpondε to a portion of the εequence of the MR22 εerotonin receptor εhown in SEQ ID NO 2, εaid polypeptide including an amino acid reεidue εequence repreεented by a formula εelected from the group conεiεting of SEQ ID NOs 38, 39, 40, 41, 47, 48, 49, 50 and 51. 44. A serotonin receptor polypeptide having a length of no more than about 100 amino acid residueε and a εequence that εubεtantially correεpondε to a portion of the εequence of the MR77 εerotonin receptor εhown in SEQ ID NO 9, εaid polypeptide including an amino acid reεidue εequence represented by a formula selected from the group consiεting of SEQ ID NOε 36, 37, 57, 58, 59, 60, 61, 62, 63, 64, 65 and 66. 45. A εerotonin receptor polypeptide having a length of no more than about 100 amino acid reεidueε and a εequence that εubεtantially correεpondε to a portion of the εequence of the MR20 εerotonin receptor εhown in SEQ ID NO 11, εaid polypeptide including an amino acid reεidue εequence repreεented by a formula εelected from the group conεiεting of SEQ ID NOε 44, 45, 46, 67, 68, 69, 70 and 71. 46. An antibody comprising antibody molecules that immunoreact with a serotonin receptor selected from the group consiεting of 5-HT 1E . like , 5-HT 5a , 5-HT 5β and 5-HT 6 . 47. The antibody of claim 46 wherein εaid antibody iε a monoclonal antibody. 48. The antibody of claim 46 wherein εaid serotonin receptor iε REC17 and εaid antibody also immunoreactε with a εerotonin receptor polypeptide εelected from the group conεiεting of SEQ ID NOε 42, 43, 52, 53, 54, 55 and 56. 49. The antibody of claim 47 wherein εaid serotonin receptor is MR22 and εaid antibody alεo immunoreacts with a serotonin receptor polypeptide selected from the group consiεting of SEQ ID NOε 38, 39, 40, 41, 47, 48, 49, 50 and 51. 50. The antibody of claim 47 wherein εaid serotonin receptor is R77 and said antibody also immunoreacts with a serotonin receptor polypeptide selected from the group consiεting of SEQ ID NOε 36, 37, 57, 58, 59, 60, 61, 62, 63, 64, 65 and 66. 51. The antibody of claim 47 wherein εaid εerotonin receptor iε MR20 and said antibody also immunoreacts with a serotonin receptor polypeptide selected from the group conεiεting of SEQ ID NOs 44, 45, 46, 67, 68, 69, 70 and 71. 52. A transgenic nonhuman mammal expresεing a DNA segment that encodes a human serotonin receptor selected from the group consiεting of 5 ~HT 1E . li(ζe , 5- HT 5α , 5-HT 5β and 5-HT 6 .

Inventors: ERLANDER MARK G, LOVENBERG TIMOTHY W, SUTCLIFFE J GREGOR, ERLANDER, MARK, G., LOVENBERG, TIMOTHY, W., SUTCLIFFE, J., GREGOR
Applicants: SCRIPPS RESEARCH INST, THE SCRIPPS RESEARCH INSTITUTE
Application year: 1994
Main classification: C07K5
IPC codes: C07K14, C12N15